• Citation: M. Cioni, D. Polino, D. Rapetti, L. Pesce, M. Delle Piane, and G.M. Pavan (2023), "Innate dynamics and identity crisis of a metal surface unveiled by machine learning of atomic environments", The Journal of Chemical Physics, 158(12), 124701. DOI: 10.1063/5.0139010.
    Abstract: Metals are traditionally considered hard matter. However, it is well known that their atomic lattices may become dynamic and undergo reconfigurations even well below the melting temperature. The innate atomic dynamics of metals is directly related to their bulk and surface properties. Understanding their complex structural dynamics is, thus, important for many applications but is not easy. Here, we report deep-potential molecular dynamics simulations allowing to resolve at an atomic resolution the complex dynamics of various types of copper (Cu) surfaces, used as an example, near the Hüttig (⁠~1/3 of melting) temperature. The development of deep neural network potential trained on density functional theory calculations provides a dynamically accurate force field that we use to simulate large atomistic models of different Cu surface types. A combination of high-dimensional structural descriptors and unsupervized machine learning allows identifying and tracking all the atomic environments (AEs) emerging in the surfaces at finite temperatures. We can directly observe how AEs that are non-native in a specific (ideal) surface, but that are, instead, typical of other surface types, continuously emerge/disappear in that surface in relevant regimes in dynamic equilibrium with the native ones. Our analyses allow estimating the lifetime of all the AEs populating these Cu surfaces and to reconstruct their dynamic interconversions networks. This reveals the elusive identity of these metal surfaces, which preserve their identity only in part and in part transform into something else under relevant conditions. This also proposes a concept of “statistical identity” for metal surfaces, which is key to understanding their behaviors and properties.

  • See Computed Properties
    Notes: This file and was provided by Matteo Cioni on June 12, 2024.
    File(s): Link(s):
    Zenodo training and results data https://zenodo.org/records/7738141
    DeePMD-kit documentation https://docs.deepmodeling.com/projects/deepmd/en/r2/

  • Citation: Y. Zuo, C. Chen, X. Li, Z. Deng, Y. Chen, J. Behler, G. Csányi, A.V. Shapeev, A.P. Thompson, M.A. Wood, and S.P. Ong (2020), "Performance and Cost Assessment of Machine Learning Interatomic Potentials", The Journal of Physical Chemistry A, 124(4), 731-745. DOI: 10.1021/acs.jpca.9b08723.
    Abstract: Machine learning of the quantitative relationship between local environment descriptors and the potential energy surface of a system of atoms has emerged as a new frontier in the development of interatomic potentials (IAPs). Here, we present a comprehensive evaluation of machine learning IAPs (ML-IAPs) based on four local environment descriptors—atom-centered symmetry functions (ACSF), smooth overlap of atomic positions (SOAP), the spectral neighbor analysis potential (SNAP) bispectrum components, and moment tensors—using a diverse data set generated using high-throughput density functional theory (DFT) calculations. The data set comprising bcc (Li, Mo) and fcc (Cu, Ni) metals and diamond group IV semiconductors (Si, Ge) is chosen to span a range of crystal structures and bonding. All descriptors studied show excellent performance in predicting energies and forces far surpassing that of classical IAPs, as well as predicting properties such as elastic constants and phonon dispersion curves. We observe a general trade-off between accuracy and the degrees of freedom of each model and, consequently, computational cost. We will discuss these trade-offs in the context of model selection for molecular dynamics and other applications.

    Notes: This is the SNAP Cu potential from the reference.

  • See Computed Properties
    Notes: Listing found at https://openkim.org.
    Link(s):
  • Citation: Y. Zuo, C. Chen, X. Li, Z. Deng, Y. Chen, J. Behler, G. Csányi, A.V. Shapeev, A.P. Thompson, M.A. Wood, and S.P. Ong (2020), "Performance and Cost Assessment of Machine Learning Interatomic Potentials", The Journal of Physical Chemistry A, 124(4), 731-745. DOI: 10.1021/acs.jpca.9b08723.
    Abstract: Machine learning of the quantitative relationship between local environment descriptors and the potential energy surface of a system of atoms has emerged as a new frontier in the development of interatomic potentials (IAPs). Here, we present a comprehensive evaluation of machine learning IAPs (ML-IAPs) based on four local environment descriptors—atom-centered symmetry functions (ACSF), smooth overlap of atomic positions (SOAP), the spectral neighbor analysis potential (SNAP) bispectrum components, and moment tensors—using a diverse data set generated using high-throughput density functional theory (DFT) calculations. The data set comprising bcc (Li, Mo) and fcc (Cu, Ni) metals and diamond group IV semiconductors (Si, Ge) is chosen to span a range of crystal structures and bonding. All descriptors studied show excellent performance in predicting energies and forces far surpassing that of classical IAPs, as well as predicting properties such as elastic constants and phonon dispersion curves. We observe a general trade-off between accuracy and the degrees of freedom of each model and, consequently, computational cost. We will discuss these trade-offs in the context of model selection for molecular dynamics and other applications.

    Notes: This is the qSNAP Cu potential from the reference.

  • See Computed Properties
    Notes: Listing found at https://openkim.org.
    Link(s):
  • Citation: S.A. Etesami, and E. Asadi (2018), "Molecular dynamics for near melting temperatures simulations of metals using modified embedded-atom method", Journal of Physics and Chemistry of Solids, 112, 61-72. DOI: 10.1016/j.jpcs.2017.09.001.
    Abstract: Availability of a reliable interatomic potential is one of the major challenges in utilizing molecular dynamics (MD) for simulations of metals at near the melting temperatures and melting point (MP). Here, we propose a novel approach to address this challenge in the concept of modified-embedded-atom (MEAM) interatomic potential; also, we apply the approach on iron, nickel, copper, and aluminum as case studies. We propose adding experimentally available high temperature elastic constants and MP of the element to the list of typical low temperature properties used for the development of MD interatomic potential parameters. We show that the proposed approach results in a reasonable agreement between the MD calculations of melting properties such as latent heat, expansion in melting, liquid structure factor, and solid-liquid interface stiffness and their experimental/computational counterparts. Then, we present the physical properties of mentioned elements near melting temperatures using the new MEAM parameters. We observe that the behavior of elastic constants, heat capacity and thermal linear expansion coefficient at room temperature compared to MP follows an empirical linear relation (α±β × MP) for transition metals. Furthermore, a linear relation between the tetragonal shear modulus and the enthalpy change from room temperature to MP is observed for face-centered cubic materials.

    Notes: S. A. Etesami (University of Memphis) noted that "We added both melting point and high temperature elastic constants into material properties database for MEAM parameter development process."

  • See Computed Properties
    Notes: These files were sent by S. A. Etesami (University of Memphis) on 23 April 2018 and posted with his permission. This version is compatible with LAMMPS.
    File(s):
  • Citation: X.-G. Li, C. Hu, C. Chen, Z. Deng, J. Luo, and S.P. Ong (2018), "Quantum-accurate spectral neighbor analysis potential models for Ni-Mo binary alloys and fcc metals", Physical Review B, 98(9), 094104. DOI: 10.1103/physrevb.98.094104.
    Abstract: In recent years, efficient interatomic potentials approaching the accuracy of density functional theory (DFT) calculations have been developed using rigorous atomic descriptors satisfying strict invariances, for example, for translation, rotation, permutation of homonuclear atoms, among others. In this paper, we generalize the spectral neighbor analysis potential (SNAP) model to bcc-fcc binary alloy systems. We demonstrate that machine-learned SNAP models can yield significant improvements even over the well-established high-performing embedded atom method (EAM) and modified EAM potentials for fcc Cu and Ni. We also report on the development of a SNAP model for the fcc Ni-bcc Mo binary system by machine learning a carefully constructed large computed data set of elemental and intermetallic compounds. We demonstrate that this binary Ni-Mo SNAP model can achieve excellent agreement with experiments in the prediction of a Ni-Mo phase diagram as well as near-DFT accuracy in the prediction of many key properties, such as elastic constants, formation energies, melting points, etc., across the entire binary composition range. In contrast, the existing Ni-Mo EAM has significant errors in the prediction of the phase diagram and completely fails in binary compounds. This paper provides a systematic model development process for multicomponent alloy systems, including an efficient procedure to optimize the hyperparameters in the model fitting, and paves the way for long-time large-scale simulations of such systems.

  • See Computed Properties
    Notes: Listing found at https://openkim.org.
    Link(s):
  • Citation: E. Asadi, M. Asle Zaeem, S. Nouranian, and M.I. Baskes (2015), "Two-phase solid-liquid coexistence of Ni, Cu, and Al by molecular dynamics simulations using the modified embedded-atom method", Acta Materialia, 86, 169-181. DOI: 10.1016/j.actamat.2014.12.010.
    Abstract: The two-phase solid–liquid coexisting structures of Ni, Cu, and Al are studied by molecular dynamics (MD) simulations using the second nearest-neighbor (2NN) modified-embedded atom method (MEAM) potential. For this purpose, the existing 2NN-MEAM parameters for Ni and Cu were modified to make them suitable for the MD simulations of the problems related to the two-phase solid–liquid coexistence of these elements. Using these potentials, we compare calculated low-temperature properties of Ni, Cu, and Al, such as elastic constants, structural energy differences, vacancy formation energy, stacking fault energies, surface energies, specific heat and thermal expansion coefficient with experimental data. The solid–liquid coexistence approach is utilized to accurately calculate the melting points of Ni, Cu, and Al. The MD calculations of the expansion in melting, latent heat and the liquid structure factor are also compared with experimental data. In addition, the solid–liquid interface free energy and surface anisotropy of the elements are determined from the interface fluctuations, and the predictions are compared to the experimental and computational data in the literature.

    Notes: Prof. Mohsen Zaeem said that this potential was designed for accurately representing properties from 0K up to the melting point.

  • LAMMPS pair_style meam (2015--Asadi-E--Cu--LAMMPS--ipr1)
    See Computed Properties
    Notes: This file was sent by Prof. Mohsen Zaeem (Missouri S&T) on 12 April 2017 and posted on 5 May 2017. Update 5 Sept 2019: The 31 July 2018 update of the repository inadvertantly replaced the parameter files with those from the 2018--Etesami-S-A--Ni--LAMMPS--ipr1 potential. The links below now point to the correct files.
    File(s):
  • Citation: R.S. Elliott, and A. Akerson (2015), "Efficient "universal" shifted Lennard-Jones model for all KIM API supported species".

    Notes: This is the Cu interaction from the "Universal" parameterization for the openKIM LennardJones612 model driver.The parameterization uses a shifted cutoff so that all interactions have a continuous energy function at the cutoff radius. This model was automatically fit using Lorentz-Berthelotmixing rules. It reproduces the dimer equilibrium separation (covalent radii) and the bond dissociation energies. It has not been fitted to other physical properties and its ability to model structures other than dimers is unknown. See the README and params files on the KIM model page for more details.

  • See Computed Properties
    Notes: Listing found at https://openkim.org.
    Link(s):
  • Citation: M.I. Mendelev, and A.H. King (2013), "The interactions of self-interstitials with twin boundaries", Philosophical Magazine, 93(10-12), 1268-1278. DOI: 10.1080/14786435.2012.747012.
    Abstract: A new mechanism of adsorption of self-interstitials onto twin boundaries (TB) in face-centred cubic (fcc) metals is identified using molecular dynamics simulations. In this mechanism, self-interstitials are arranged in the twin boundary plane forming a previously unknown kind of self-interstitial cluster. The self-interstitial cluster in the twin boundary is bounded by lines of atoms under high hydrostatic pressure while the pressure inside the cluster is much smaller. The atoms in the middle of the cluster have hcp short range order rather than fcc. However, if a new self-interstitial cluster forms in the middle of a pre-existing one, then the atoms in the middle of the new cluster will have regular twin boundary coordination. As a consequence of the formation of self-interstitial clusters inside each other, TB can be powerful, non-saturating sinks for self-interstitials.

    Notes: Update 2018-06-12: Publication information added.

  • LAMMPS pair_style eam/fs (2012--Mendelev-M-I--Cu--LAMMPS--ipr1)
    See Computed Properties
    Notes: This file was provided by Mikhail Mendelev (Ames Laboratory) and posted with his permission on 25 Jul. 2012. He noted that "This potential is an improvement of Cu1 (2008--Mendelev-M-I-Kramer-M-J-Becker-C-A-Asta-M--Cu) to better describe stacking fault energies." Update 19 July 2021: The contact email in the file's header has been changed. Update Jan 14 2022: Citation information has been updated in the file's header.
    File(s):
  • See Computed Properties
    Notes: Listing found at https://openkim.org. This KIM potential is based on the files from 2012--Mendelev-M-I--Cu--LAMMPS--ipr1.
    Link(s):
  • Citation: M.I. Mendelev, M.J. Kramer, C.A. Becker, and M. Asta (2008), "Analysis of semi-empirical interatomic potentials appropriate for simulation of crystalline and liquid Al and Cu", Philosophical Magazine, 88(12), 1723-1750. DOI: 10.1080/14786430802206482.
    Abstract: We investigate the application of embedded atom method (EAM) interatomic potentials in the study of crystallization kinetics from deeply undercooled melts, focusing on the fcc metals Al and Cu. For this application, it is important that the EAM potential accurately reproduces melting properties and liquid structure, in addition to the crystalline properties most commonly fit in its development. To test the accuracy of previously published EAM potentials and to guide the development of new potential in this work, first-principles calculations have been performed and new experimental measurements of the Al and Cu liquid structure factors have been undertaken by X-ray diffraction. We demonstrate that the previously published EAM potentials predict a liquid structure that is too strongly ordered relative to measured diffraction data. We develop new EAM potentials for Al and Cu to improve the agreement with the first-principles and measured liquid diffraction data. Furthermore, we calculate liquid-phase diffusivities and find that this quantity correlates well with the liquid structure. Finally, we perform molecular dynamics simulations of crystal nucleation from the melt during quenching at constant cooling rate. We find that EAM potentials, which predict the same zero-temperature crystal properties but different liquid structures, can lead to quite different crystallization kinetics. More interestingly, we find that two potentials predicting very similar equilibrium solid and liquid properties can still produce very different crystallization kinetics under far-from-equilibrium conditions characteristic of the rapid quenching simulations employed here.

  • LAMMPS pair_style eam/fs (2008--Mendelev-M-I--Cu--LAMMPS--ipr1)
    See Computed Properties
    Notes: This file was provided by Mikhail Mendelev (Ames Laboratory) and posted with his permission on 14 Oct. 2010. He noted that it is the Cu potential used for 2007--Mendelev-M-I-Sordelet-D-J-Kramer-M-J--Cu-Zr and 2009--Mendelev-M-I-Kramer-M-J-Ott-R-T-et-al--Cu-Zr, though the files are different due to transformations of the density and embedding energy functions which do not affect the pure element properties. Update 19 July 2021: The contact email in the file's header has been changed.
    File(s):
  • See Computed Properties
    Notes: Listing found at https://openkim.org. This KIM potential is based on the files from 2008--Mendelev-M-I--Cu--LAMMPS--ipr1.
    Link(s):
  • Citation: X.W. Zhou, R.A. Johnson, and H.N.G. Wadley (2004), "Misfit-energy-increasing dislocations in vapor-deposited CoFe/NiFe multilayers", Physical Review B, 69(14), 144113. DOI: 10.1103/physrevb.69.144113.
    Abstract: Recent molecular dynamics simulations of the growth of [Ni0.8Fe0.2/Au] multilayers have revealed the formation of misfit-strain-reducing dislocation structures very similar to those observed experimentally. Here we report similar simulations showing the formation of edge dislocations near the interfaces of vapor-deposited (111) [NiFe/CoFe/Cu] multilayers. Unlike misfit dislocations that accommodate lattice mismatch, the dislocation structures observed here increase the mismatch strain energy. Stop-action observations of the dynamically evolving atomic structures indicate that during deposition on the (111) surface of a fcc lattice, adatoms may occupy either fcc sites or hcp sites. This results in the random formation of fcc and hcp domains, with dislocations at the domain boundaries. These dislocations enable atoms to undergo a shift from fcc to hcp sites, or vice versa. These shifts lead to missing atoms, and therefore a later deposited layer can have missing planes compared to a previously deposited layer. This dislocation formation mechanism can create tensile stress in fcc films. The probability that such dislocations are formed was found to quickly diminish under energetic deposition conditions.

  • FORTRAN (2004--Zhou-X-W--Cu--FORTRAN--ipr1)
    Notes: These are the original files sent by X.W. Zhou (Sandia National Laboratory) and posted with his permission. C.A. Becker (NIST) modified create.f to include the reference in the generated potential files and the EAM.input file for this composition. These files can be used to generate alloy potentials for Cu, Ag, Au, Ni, Pd, Pt, Al, Pb, Fe, Mo, Ta, W, Mg, Co, Ti, and Zr by editing EAM.input. However, as addressed in the reference, these potentials were not designed for use with metal compounds.
    File(s): superseded


  • LAMMPS pair_style eam/alloy (2004--Zhou-X-W--Cu--LAMMPS--ipr1)
    See Computed Properties
    Notes: This file was generated by C.A. Becker (NIST) from create.f and posted with X.W. Zhou's (Sandia National Laboratory) permission.
    File(s): superseded


  • FORTRAN (2004--Zhou-X-W--Cu--FORTRAN--ipr2)
    Notes: The file Zhou04_create_v2.f is an updated version of create.f modified by L.M. Hale (NIST) following advice from X.W. Zhou (Sandia National Laboratory). This version removes spurious fluctuations in the tabulated functions of the original potential files caused by single/double precision floating point number conflicts.
    File(s):
  • LAMMPS pair_style eam/alloy (2004--Zhou-X-W--Cu--LAMMPS--ipr2)
    See Computed Properties
    Notes: This file was generated by L.M. Hale from Zhou04_create_v2.f on 13 April 2018 and posted with X.W. Zhou's (Sandia National Laboratory) permission. This version corrects an issue with spurious fluctuations in the tabulated functions.
    File(s):
  • See Computed Properties
    Notes: Listing found at https://openkim.org. This KIM potential is based on the files from 2004--Zhou-X-W--Cu--LAMMPS--ipr1.
    Link(s):
  • See Computed Properties
    Notes: Listing found at https://openkim.org. This KIM potential is based on the files from 2004--Zhou-X-W--Cu--LAMMPS--ipr2.
    Link(s):
  • Citation: Y. Mishin, M.J. Mehl, D.A. Papaconstantopoulos, A.F. Voter, and J.D. Kress (2001), "Structural stability and lattice defects in copper: Ab initio, tight-binding, and embedded-atom calculations", Physical Review B, 63(22), 224106. DOI: 10.1103/physrevb.63.224106.
    Abstract: We evaluate the ability of the embedded-atom method (EAM) potentials and the tight-binding (TB) method to predict reliably energies and stability of nonequilibrium structures by taking Cu as a model material. Two EAM potentials are used here. One is constructed in this work by using more fitting parameters than usual and including ab initio energies in the fitting database. The other potential was constructed previously using a traditional scheme. Excellent agreement is observed between ab initio, TB, and EAM results for the energies and stability of several nonequilibrium structures of Cu, as well as for energies along deformation paths between different structures. We conclude that not only TB calculations but also EAM potentials can be suitable for simulations in which correct energies and stability of different atomic configurations are essential, at least for Cu. The bcc, simple cubic, and diamond structures of Cu were identified as elastically unstable, while some other structures (e.g., hcp and 9R) are metastable. As an application of this analysis, nonequilibrium structures of epitaxial Cu films on (001)-oriented fcc or bcc substrates are evaluated using a simple model and atomistic simulations with an EAM potential. In agreement with experimental data, the structure of the film can be either deformed fcc or deformed hcp. The bcc structure cannot be stabilized by epitaxial constraints.

    Notes: This listing is for the reference's EAM1 potential.

  • EAM tabulated functions (2001--Mishin-Y--Cu-1--table--ipr1)
    Notes: These files were provided by Yuri Mishin.
    File(s):
    F(ρ): F_cu.plt
    ρ(r): fcu.plt
    φ(r): pcu.plt

  • LAMMPS pair_style eam/alloy (2001--Mishin-Y--Cu-1--LAMMPS--ipr1)
    See Computed Properties
    Notes: This conversion was produced by Chandler Becker on 4 February 2009 from the plt files listed above. This version is compatible with LAMMPS. Validation and usage information can be found in Cu01_releaseNotes_1.pdf. If you use this setfl file, please credit the website in addition to the original reference.
    File(s):
  • See Computed Properties
    Notes: Listing found at https://openkim.org. This KIM potential is based on the files from 2001--Mishin-Y--Cu-1--LAMMPS--ipr1.
    Link(s):
  • Citation: Y. Mishin, M.J. Mehl, D.A. Papaconstantopoulos, A.F. Voter, and J.D. Kress (2001), "Structural stability and lattice defects in copper: Ab initio, tight-binding, and embedded-atom calculations", Physical Review B, 63(22), 224106. DOI: 10.1103/physrevb.63.224106.
    Abstract: We evaluate the ability of the embedded-atom method (EAM) potentials and the tight-binding (TB) method to predict reliably energies and stability of nonequilibrium structures by taking Cu as a model material. Two EAM potentials are used here. One is constructed in this work by using more fitting parameters than usual and including ab initio energies in the fitting database. The other potential was constructed previously using a traditional scheme. Excellent agreement is observed between ab initio, TB, and EAM results for the energies and stability of several nonequilibrium structures of Cu, as well as for energies along deformation paths between different structures. We conclude that not only TB calculations but also EAM potentials can be suitable for simulations in which correct energies and stability of different atomic configurations are essential, at least for Cu. The bcc, simple cubic, and diamond structures of Cu were identified as elastically unstable, while some other structures (e.g., hcp and 9R) are metastable. As an application of this analysis, nonequilibrium structures of epitaxial Cu films on (001)-oriented fcc or bcc substrates are evaluated using a simple model and atomistic simulations with an EAM potential. In agreement with experimental data, the structure of the film can be either deformed fcc or deformed hcp. The bcc structure cannot be stabilized by epitaxial constraints.

    Notes: This listing is for the reference's EAM2 potential.

  • EAM tabulated functions (2001--Mishin-Y--Cu-2--table--ipr1)
    Notes: These files were provided by Yuri Mishin and posted on 10 Dec. 2009.
    File(s):
  • Citation: X.W. Zhou, H.N.G. Wadley, R.A. Johnson, D.J. Larson, N. Tabat, A. Cerezo, A.K. Petford-Long, G.D.W. Smith, P.H. Clifton, R.L. Martens, and T.F. Kelly (2001), "Atomic scale structure of sputtered metal multilayers", Acta Materialia, 49(19), 4005-4015. DOI: 10.1016/s1359-6454(01)00287-7.
    Abstract: A combined theoretical and experimental approach has been used to study nanoscale CoFe/Cu/CoFe multilayer films grown by sputter deposition. Such films have applications in sensors that utilize the giant magnetoresistance effect, for example, read heads in high-density information storage devices. Atomistic simulations based on a molecular dynamics approach and an alloy form of the embedded atom method have been developed to accurately model the sputter deposition of the CoFe/Cu/CoFe multilayers. The simulations show that relatively flat interfaces are formed because of the energetic deposition conditions. However, significant intermixing at the CoFe-on-Cu interface, but not at the Cu-on-CoFe interface, was observed. An abnormal Fe depletion zone is also revealed at the CoFe-on-Cu interface. A three-dimensional atom probe method has been used for a nanoscale chemical analysis of the films. It provided direct verification of the simulations. The simulations have then been used to understand the mechanism responsible for the formation of the intermixing defects observed in the multilayers. A novel deposition technique is proposed which reduces both interfacial mixing and Fe depletion by controlling the incident adatom energies.

    Notes: This is superseded by 2004--Zhou-X-W-Johnson-R-A-Wadley-H-N-G--Cu, which gives a slightly different parameterization.

  • See Computed Properties
    Notes: Listing found at https://openkim.org. This KIM potential is based on the Cu_zhou.eam.alloy file from the LAMMPS potentials folder dated 2007-10-12 and listed as having been contributed by G. Ziegenhain.
    Link(s): superseded


  • Citation: K.W. Jacobsen, P. Stoltze, and J.K. Nørskov (1996), "A semi-empirical effective medium theory for metals and alloys", Surface Science, 366(2), 394-402. DOI: 10.1016/0039-6028(96)00816-3.
    Abstract: A detailed derivation of the simplest form of the effective medium theory for bonding in metallic systems is presented, and parameters for the fcc metals Ni, Pd, Pt, Cu, Ag and Au are given. The derivation of parameters is discussed in detail to show how new parameterizations can be made. The method and the parameterization is tested for a number of surface and bulk problems. In particular we present calculations of the energetics of metal atoms deposited on metal surfaces. The calculated energies include heats of adsorption, energies of overlayers, both pseudomorphic and relaxed, as well as energies of atoms alloyed into the first surface layer.

  • Citation: G.J. Ackland, and V. Vitek (1990), "Many-body potentials and atomic-scale relaxations in noble-metal alloys", Physical Review B, 41(15), 10324-10333. DOI: 10.1103/physrevb.41.10324.
    Abstract: We derive empirical many-body potentials for noble-metal alloy systems in the framework of the Finnis-Sinclair model [Philos. Mag. A 50, 45 (1984)] which is based on a second-moment approximation to the tight-binding density of states for transition metals [F. Cyrot, J. Phys. Chem. Solids 29, 1235 (1968)]. The most important extension of the model is a simple incorporation of interspecies interactions which involves fitting the alloying energies. The importance of properly accounting for the local atomic relaxations when constructing the potentials is emphasized. The observed principal features of the phase diagrams of the alloys are all well reproduced by this scheme. Furthermore, reasonable concentration dependences of the alloy lattice parameter and elastic constants are obtained. This leads us to suggest that fine details of the electronic structure may be less important in determining atomic structures than are more global parameters such as atomic sizes and binding energies.

  • LAMMPS pair_style eam/fs (1990--Ackland-G-J--Cu--LAMMPS--ipr1)
    See Computed Properties
    Notes: A conversion to LAMMPS from MOLDY was performed by G.J. Ackland and submitted on 10 Oct. 2017. This implementation includes the short-range repulsion for radiation studies. Update March 15, 2020: This version was identified to not be compatible with LAMMPS.
    File(s): retracted


  • LAMMPS pair_style eam/fs (1990--Ackland-G-J--Cu--LAMMPS--ipr2)
    See Computed Properties
    Notes: This file was posted on 15 March 2020. It corrects the 4th line to be compatible with LAMMPS.
    File(s):
  • See Computed Properties
    Notes: Listing found at https://openkim.org. This KIM potential is based on the files from 1990--Ackland-G-J--Cu--LAMMPS--ipr1.
    Link(s):
  • Citation: J.B. Adams, S.M. Foiles, and W.G. Wolfer (1989), "Self-diffusion and impurity diffusion of fcc metals using the five-frequency model and the Embedded Atom Method", Journal of Materials Research, 4(1), 102-112. DOI: 10.1557/jmr.1989.0102.
    Abstract: The activation energies for self-diffusion of transition metals (Au, Ag, Cu, Ni, Pd, Pt) have been calculated with the Embedded Atom Method (EAM); the results agree well with available experimental data for both mono-vacancy and di-vacancy mechanisms. The EAM was also used to calculate activation energies for vacancy migration near dilute impurities. These energies determine the atomic jump frequencies of the classic "five-frequency formula," which yields the diffusion rates of impurities by a mono-vacancy mechanism. These calculations were found to agree fairly well with experiment and with Neumann and Hirschwald's "Tm" model.

  • See Computed Properties
    Notes: cuu6.txt was obtained from http://enpub.fulton.asu.edu/cms/ potentials/main/main.htm and posted with the permission of J.B. Adams. The name of the file was retained, even though the header information lists the potential as 'universal 4.' Except for the first comment line, this file is identical to "Cu_u6.eam" in the August 22, 2018 LAMMPS distribution.
    File(s):
  • See Computed Properties
    Notes: Listing found at https://openkim.org. This KIM potential is based on the same files as 1989--Adams-J-B--Cu--LAMMPS--ipr1.
    Link(s):
  • Citation: R.A. Johnson (1988), "Analytic nearest-neighbor model for fcc metals", Physical Review B, 37(8), 3924-3931. DOI: 10.1103/physrevb.37.3924.
    Abstract: The implications of the mathematical format of the embedded-atom method of computer modeling of metals have been studied with use of a simple nearest-neighbor analytic model for the fcc lattice. The physical inputs into the model are the atomic volume, the cohesive energy, the bulk modulus, the average shear modulus, the vacancy-formation energy, and the slope at the nearest-neighbor distance of the spherically averaged free-atom electron density calculated with Hartree-Fock theory. The model employs an exponential repulsion between nearest-neighboring atoms, an exponentially decreasing function for the free-atom electron density, and a universal equation relating the crystal energy and the lattice constant. The anisotropy ratio of the cubic shear moduli is constrained to be 2 with this model. The dependence of the energies for unrelaxed configurations for vacancy formation, divacancy binding, and low-index plane surfaces on the model parameters has been analyzed. The average shear modulus plays a dominant role in determining these energies relative to the bulk modulus or the cohesive energy because the slope of the embedding function at the equilibrium electron density is linear in the average shear modulus. Embedding functions are not uniquely determined in specific models, and it is shown that the embedding functions used in several models are essentially equivalent.

  • See Computed Properties
    Notes: Listing found at https://openkim.org.
    Link(s):
  • Citation: G.J. Ackland, G. Tichy, V. Vitek, and M.W. Finnis (1987), "Simple N-body potentials for the noble metals and nickel", Philosophical Magazine A, 56(6), 735-756. DOI: 10.1080/01418618708204485.
    Abstract: Using the approach of Finnis and Sinclair, N-body potentials for copper, silver, gold and nickel have been constructed. The total energy is regarded as consisting of a pair-potential part and a many body cohesive part. Both these parts are functions of the atomic separations only and are represented by cubic splines, fitted to various bulk properties. For the noble metals, the pair-potentials were fitted at short range to pressure-volume relationships calculated by Christensen and Heine so that interactions at separations smaller than that of the first-nearest neighbours can be treated in this scheme. Using these potentials, point defects, surfaces (including the surface reconstructions) and grain boundaries have been studied and satisfactory agreement with available experimental data has been found.

  • Moldy FS (1987--Ackland-G-J--Cu--MOLDY--ipr1)
    Notes: The parameters in cu.moldy were obtained from http://homepages.ed.ac.uk/graeme/moldy/moldy.html and posted with the permission of G.J. Ackland.
    File(s):
  • LAMMPS pair_style eam/fs (1987--Ackland-G-J--Cu--LAMMPS--ipr1)
    See Computed Properties
    Notes: This conversion was performed from G.J. Ackland's parameters by M.I. Mendelev. Conversion checks from M.I. Mendelev can be found in the conversion_check.pdf. These files were posted on 30 June 2009 with the permission of G.J. Ackland and M.I. Mendelev. These potentials are not designed for simulations of radiation damage. Update 19 July 2021: The contact email in the file's header has been changed.
    File(s):
  • LAMMPS pair_style eam/fs (1987--Ackland-G-J--Cu--LAMMPS--ipr2)
    See Computed Properties
    Notes: A new conversion to LAMMPS performed by G.J. Ackland was submitted on 10 Oct. 2017. This version adds close-range repulsion for radiation studies.
    File(s):
  • See Computed Properties
    Notes: Listing found at https://openkim.org. This KIM potential is based on the files from 1987--Ackland-G-J--Cu--LAMMPS--ipr1.
    Link(s):
  • See Computed Properties
    Notes: Listing found at https://openkim.org. This KIM potential is based on the files from 1987--Ackland-G-J--Cu--LAMMPS--ipr2.
    Link(s):
  • Citation: S.M. Foiles, M.I. Baskes, and M.S. Daw (1986), "Embedded-atom-method functions for the fcc metals Cu, Ag, Au, Ni, Pd, Pt, and their alloys", Physical Review B, 33(12), 7983-7991. DOI: 10.1103/physrevb.33.7983.
    Abstract: A consistent set of embedding functions and pair interactions for use with the embedded-atom method [M.S. Daw and M. I. Baskes, Phys. Rev. B 29, 6443 (1984)] have been determined empirically to describe the fcc metals Cu, Ag, Au, Ni, Pd, and Pt as well as alloys containing these metals. The functions are determined empirically by fitting to the sublimation energy, equilibrium lattice constant, elastic constants, and vacancy-formation energies of the pure metals and the heats of solution of the binary alloys. The validity of the functions is tested by computing a wide range of properties: the formation volume and migration energy of vacancies, the formation energy, formation volume, and migration energy of divacancies and self-interstitials, the surface energy and geometries of the low-index surfaces of the pure metals, and the segregation energy of substitutional impurities to (100) surfaces.

  • See Computed Properties
    Notes: This file was taken from the August 22, 2018 LAMMPS distribution.
    File(s):
  • See Computed Properties
    Notes: Listing found at https://openkim.org. This KIM potential is based on the same files as 1986--Foiles-S-M--Cu--LAMMPS--ipr1.
    Link(s):
  • Citation: R.A. MacDonald, and W.M. MacDonald (1981), "Thermodynamic properties of fcc metals at high temperatures", Physical Review B, 24(4), 1715-1724. DOI: 10.1103/physrevb.24.1715.
    Abstract: We have carried out an exact and consistent calculation of the thermodynamic properties of monatomic fcc crystals at high temperatures. These properties are obtained from the Helmholtz free energy of the crystal F(V,T) by means of the appropriate thermodynamic relations. It is crucial to the success of the calculation that we have been able to obtain the volume dependence of the free energy. F(V,T) includes the static lattice energy and the vibrational contributions from the harmonic and lowest-order (cubic and quartic) anharmonic terms in perturbation theory evaluated in the high-temperature limit. The atoms interact via an effective nearest-neighbor central-force potential φ(r). We have calculated the specific heat at constant volume and at constant pressure, the thermal expansion, the coefficient of linear expansion, the isothermal and adiabatic bulk moduli, and the Grüneisen parameter for the following fcc metals: Cu, Ag, Ca, Sr, Al, Pb, and Ni. Good agreement with experiment is obtained in all cases. We discuss the implications of these results for further studies of the properties of metals.

  • See Computed Properties
    Notes: Listing found at https://openkim.org.
    Link(s):
 
  • Citation: X.W. Zhou, R.A. Johnson, and H.N.G. Wadley (2004), "Misfit-energy-increasing dislocations in vapor-deposited CoFe/NiFe multilayers", Physical Review B, 69(14), 144113. DOI: 10.1103/physrevb.69.144113.
    Abstract: Recent molecular dynamics simulations of the growth of [Ni0.8Fe0.2/Au] multilayers have revealed the formation of misfit-strain-reducing dislocation structures very similar to those observed experimentally. Here we report similar simulations showing the formation of edge dislocations near the interfaces of vapor-deposited (111) [NiFe/CoFe/Cu] multilayers. Unlike misfit dislocations that accommodate lattice mismatch, the dislocation structures observed here increase the mismatch strain energy. Stop-action observations of the dynamically evolving atomic structures indicate that during deposition on the (111) surface of a fcc lattice, adatoms may occupy either fcc sites or hcp sites. This results in the random formation of fcc and hcp domains, with dislocations at the domain boundaries. These dislocations enable atoms to undergo a shift from fcc to hcp sites, or vice versa. These shifts lead to missing atoms, and therefore a later deposited layer can have missing planes compared to a previously deposited layer. This dislocation formation mechanism can create tensile stress in fcc films. The probability that such dislocations are formed was found to quickly diminish under energetic deposition conditions.

    Notes: This is a combined potential that contains all 16 elements from the source reference. It is provided here due to various requests for more elemental combinations often for high entropy simulations. As a caution, note that all of the cross interactions are determined through a universal mixing function and that most elemental systems were not thoroughly explored and tested by the original authors meaning that most binary and higher-order systems may not be well optimized.

  • See Computed Properties
    Notes: This file was generated by Ilia Nikiforov using the Zhou04_create_v2.f FORTRAN code which can be found on the associated elemental listings. The code was slightly modified to increase the tabulation points to 3000 to ensure good interpolations of the embedding energy function for all elements as W has a noticeably larger delta rho than the other elements. Also, the header was fixed to include all 16 element symbol tags.
    File(s):
 
 
  • Citation: X.W. Zhou, R.A. Johnson, and H.N.G. Wadley (2004), "Misfit-energy-increasing dislocations in vapor-deposited CoFe/NiFe multilayers", Physical Review B, 69(14), 144113. DOI: 10.1103/physrevb.69.144113.
    Abstract: Recent molecular dynamics simulations of the growth of [Ni0.8Fe0.2/Au] multilayers have revealed the formation of misfit-strain-reducing dislocation structures very similar to those observed experimentally. Here we report similar simulations showing the formation of edge dislocations near the interfaces of vapor-deposited (111) [NiFe/CoFe/Cu] multilayers. Unlike misfit dislocations that accommodate lattice mismatch, the dislocation structures observed here increase the mismatch strain energy. Stop-action observations of the dynamically evolving atomic structures indicate that during deposition on the (111) surface of a fcc lattice, adatoms may occupy either fcc sites or hcp sites. This results in the random formation of fcc and hcp domains, with dislocations at the domain boundaries. These dislocations enable atoms to undergo a shift from fcc to hcp sites, or vice versa. These shifts lead to missing atoms, and therefore a later deposited layer can have missing planes compared to a previously deposited layer. This dislocation formation mechanism can create tensile stress in fcc films. The probability that such dislocations are formed was found to quickly diminish under energetic deposition conditions.

  • FORTRAN (2004--Zhou-X-W--Cu-Ag-Au--FORTRAN--ipr1)
    Notes: These are the original files sent by X.W. Zhou (Sandia National Laboratory) and posted with his permission. C.A. Becker (NIST) modified create.f to include the reference in the generated potential files and the EAM.input file for this composition. These files can be used to generate alloy potentials for Cu, Ag, Au, Ni, Pd, Pt, Al, Pb, Fe, Mo, Ta, W, Mg, Co, Ti, and Zr by editing EAM.input. However, as addressed in the reference, these potentials were not designed for use with metal compounds.
    File(s): superseded


  • LAMMPS pair_style eam/alloy (2004--Zhou-X-W--Cu-Ag-Au--LAMMPS--ipr1)
    See Computed Properties
    Notes: This file was generated by C.A. Becker (NIST) from create.f and posted with X.W. Zhou's (Sandia National Laboratory) permission.
    File(s): superseded


  • FORTRAN (2004--Zhou-X-W--Cu-Ag-Au--FORTRAN--ipr2)
    Notes: The file Zhou04_create_v2.f is an updated version of create.f modified by L.M. Hale (NIST) following advice from X.W. Zhou (Sandia National Laboratory). This version removes spurious fluctuations in the tabulated functions of the original potential files caused by single/double precision floating point number conflicts.
    File(s):
  • LAMMPS pair_style eam/alloy (2004--Zhou-X-W--Cu-Ag-Au--LAMMPS--ipr2)
    See Computed Properties
    Notes: This file was generated by L.M. Hale from Zhou04_create_v2.f on 13 April 2018 and posted with X.W. Zhou's (Sandia National Laboratory) permission. This version corrects an issue with spurious fluctuations in the tabulated functions.
    File(s):
  • See Computed Properties
    Notes: Listing found at https://openkim.org. This KIM potential is based on the files from 2004--Zhou-X-W--Cu-Ag-Au--LAMMPS--ipr2.
    Link(s):
  • Citation: G.J. Ackland, and V. Vitek (1990), "Many-body potentials and atomic-scale relaxations in noble-metal alloys", Physical Review B, 41(15), 10324-10333. DOI: 10.1103/physrevb.41.10324.
    Abstract: We derive empirical many-body potentials for noble-metal alloy systems in the framework of the Finnis-Sinclair model [Philos. Mag. A 50, 45 (1984)] which is based on a second-moment approximation to the tight-binding density of states for transition metals [F. Cyrot, J. Phys. Chem. Solids 29, 1235 (1968)]. The most important extension of the model is a simple incorporation of interspecies interactions which involves fitting the alloying energies. The importance of properly accounting for the local atomic relaxations when constructing the potentials is emphasized. The observed principal features of the phase diagrams of the alloys are all well reproduced by this scheme. Furthermore, reasonable concentration dependences of the alloy lattice parameter and elastic constants are obtained. This leads us to suggest that fine details of the electronic structure may be less important in determining atomic structures than are more global parameters such as atomic sizes and binding energies.

  • See Computed Properties
    Notes: These files were provided by Jyri Kimari on 8 May 2023. The code_and_tests.zip folder contains the fortran program and input file used to generate the eam.fs file, plots of the potential functions,and plots of the binary alloying energies. For the alloying energies, two sizes were investigated (256 atoms and 32000 atoms) which respectively agree with the local and hydrostatic configurational sampling models (LCSM and HCSM) reported in the paper.
    File(s):
 
 
  • Citation: H.H. Wu, and D.R. Trinkle (2009), "Cu/Ag EAM potential optimized for heteroepitaxial diffusion from ab initio data", Computational Materials Science, 47(2), 577-583. DOI: 10.1016/j.commatsci.2009.09.026.
    Abstract: A binary embedded-atom method (EAM) potential is optimized for Cu on Ag(1 1 1) by fitting to ab initio data. The fitting database consists of DFT calculations of Cu monomers and dimers on Ag(1 1 1), specifically their relative energies, adatom heights, and dimer separations. We start from the Mishin Cu–Ag EAM potential and first modify the Cu–Ag pair potential to match the FCC/HCP site energy difference then include Cu–Cu pair potential optimization for the entire database. The potential generated from this optimization method gives better agreement to DFT calculations of Cu monomers, dimers, and trimers than previous EAMs as well as a SEAM optimized potential. In trimer calculations, the optimized potential produces the DFT relative energy between FCC and HCP trimers, though a different ground state is predicted. We use the optimized potential to calculate diffusion barriers for Cu monomers, dimers, and trimers. The predicted monomer barrier is the same as DFT, while experimental barriers for monomers and dimers are lower than predicted here. We attribute the difference with experiment to the overestimation of surface adsorption energies by DFT and a simple correction is presented. Our results show that this optimization method is suitable for other heteroepitaxial systems; and that the optimized Cu–Ag EAM can be applied in the study of larger Cu islands on Ag(1 1 1).

    Notes: 7 May 2010 Update: Reference changed from 'in preparation' at the request of Henry Wu (Univ. of Illinois).

  • LAMMPS pair_style eam/alloy (2009--Wu-H-H--Cu-Ag--LAMMPS--ipr1)
    See Computed Properties
    Notes: This file was provided by Henry H. Wu and posted with his permission. He also supplied a new file where the first line of the header was updated to reflect the publication status.
    File(s):
  • See Computed Properties
    Notes: Listing found at https://openkim.org. This KIM potential is based on the files from 2009--Wu-H-H--Cu-Ag--LAMMPS--ipr1.
    Link(s):
 
 
  • Citation: A. Mahata, T. Mukhopadhyay, and M. Asle Zaeem (2022), "Modified embedded-atom method interatomic potentials for Al-Cu, Al-Fe and Al-Ni binary alloys: From room temperature to melting point", Computational Materials Science, 201, 110902. DOI: 10.1016/j.commatsci.2021.110902.
    Abstract: Second nearest neighbor modified embedded-atom method (2NN-MEAM) interatomic potentials are developed for binary aluminum (Al) alloys applicable from room temperature to the melting point. The binary alloys studied in this work are Al-Cu, Al-Fe and Al-Ni. Sensitivity and uncertainty analyses are performed on potential parameters based on the perturbation approach. The outcome of the sensitivity analysis shows that some of the MEAM parameters interdependently influence all MEAM model outputs, allowing for the definition of an ordered calibration procedure to target specific MEAM outputs. Using these 2NN-MEAM interatomic potentials, molecular dynamics (MD) simulations are performed to calculate low and high-temperature properties, such as the formation energies of stable phases and unstable intermetallics, lattice parameters, elastic constants, thermal expansion coefficients, enthalpy of formation of solids, liquid mixing enthalpy, and liquidus temperatures at a wide range of compositions. The computed data are compared with the available first principle calculations and experimental data, showing high accuracy of the 2NN-MEAM interatomic potentials. In addition, the liquidus temperature of the Al binary alloys is compared to the phase diagrams determined by the CALPHAD method.

  • See Computed Properties
    Notes: These files were provided by Mohsen Asle Zaeem on Oct 8, 2021 and posted with his permission.
    File(s):
  • Citation: X.W. Zhou, D.K. Ward, and M.E. Foster (2016), "An analytical bond-order potential for the aluminum copper binary system", Journal of Alloys and Compounds, 680, 752-767. DOI: 10.1016/j.jallcom.2016.04.055.
    Abstract: Al-rich Al1−xCux alloys are important structural materials in the aerospace industry due to their high strength to density ratio. They are also emerging materials for hydrogen containing structures due to their potentially high resistance to hydrogen embrittlement. To enable accurate simulations of the mechanical behavior of Al1−xCux alloys that can guide material improvement, we have developed a high-fidelity analytical bond-order potential (BOP) for the Al-Cu system (the code is publically available in molecular dynamics package LAMMPS). The formalism of the potential is derived from quantum mechanical theories, and the parameters are optimized in an iteration fashion. The iterations begin by fitting properties of a variety of elemental and compound configurations (with coordination varying from 1 to 12) including small clusters, bulk lattices, defects, and surfaces. Following the fitting process, crystalline growth of important equilibrium phases is checked through molecular dynamics simulations of vapor deposition. It is demonstrated that this Al-Cu bond-order potential has unique advantages relative to existing literature potentials in reproducing structural and property tends from experiments and quantum-mechanical calculations, and providing good descriptions of melting temperature, defect characteristics, and surface energies. Most importantly, this BOP is the only potential currently available capable of capturing the Al-rich end of the Al-Cu phase diagram. This capability is rigorously verified by the potential's ability to capture the crystalline growth of the ground-state structures for elemental Al and Cu, as well as, the θ and θ′ phases of the Al2Cu compound in vapor deposition simulations.

  • See Computed Properties
    Notes: This file was taken from the August 22, 2018 LAMMPS distribution and listed as having been created by X.W. Zhou (Sandia) Update Jan 15, 2020: It was noticed that the original file hosted here was truncated and incomplete. The incomplete file will not work with LAMMPS versions after 7 Aug 2019. For earlier LAMMPS versions, both versions of the parameter file appear to behave identically.
    File(s): superseded


  • See Computed Properties
    Notes: This file was provided by Xiaowang Zhou (Sandia) on Dec 19, 2019. Unlike the eariler implementation above, this file is complete and should work with any version of LAMMPS that supports the bop pair style.
    File(s):
  • Citation: J. Cai, and Y.Y. Ye (1996), "Simple analytical embedded-atom-potential model including a long-range force for fcc metals and their alloys", Physical Review B, 54(12), 8398-8410. DOI: 10.1103/physrevb.54.8398.
    Abstract: A simple analytical embedded-atom method (EAM) model is developed. The model includes a long-range force. In this model, the electron-density function is taken as a decreasing exponential function, the two-body potential is defined as a function like a form given by Rose et al. [Phys. Rev. B 33, 7983 (1986)], and the embedding energy is assumed to be an universal form recently suggested by Banerjea and Smith. The embedding energy has a positive curvature. The model is applied to seven fcc metals (Al, Ag, Au, Cu, Ni, Pd, and Pt) and their binary alloys. All the considered properties, whether for pure metal systems or for alloy systems, are predicted to be satisfactory at least qualitatively. The model resolves the problems of Johnson’s model for predicting the properties of the alloys involving metal Pd. However, more importantly, (i) by investigating the structure stability of seven fcc metals using the present model, we found that the stability energy is dominated by both the embedding energy and the pair potential for fcc-bcc stability while the pair potential dominates and is underestimated for fcc-hcp stability; and (ii) we find that the predicted total energy as a function of lattice parameter is in good agreement with the equation of state of Rose et al. for all seven fcc metals, and that this agreement is closely related to the electron density, i.e., the lower the contribution from atoms of the second-nearest neighbor to host density, the better the agreement becomes. We conclude the following: (i) for an EAM, where angle force is not considered, the long-range force is necessary for a prediction of the structure stability; or (ii) the dependence of the electron density on angle should be considered so as to improve the structure-stability energy. The conclusions are valid for all EAM models where an angle force is not considered.

  • See Computed Properties
    Notes: Listing found at https://openkim.org.
    Link(s):
 
  • Citation: B. Jelinek, S. Groh, M.F. Horstemeyer, J. Houze, S.G. Kim, G.J. Wagner, A. Moitra, and M.I. Baskes (2012), "Modified embedded atom method potential for Al, Si, Mg, Cu, and Fe alloys", Physical Review B, 85(24), 245102. DOI: 10.1103/physrevb.85.245102.
    Abstract: A set of modified embedded-atom method (MEAM) potentials for the interactions between Al, Si, Mg, Cu, and Fe was developed from a combination of each element's MEAM potential in order to study metal alloying. Previously published MEAM parameters of single elements have been improved for better agreement to the generalized stacking fault energy (GSFE) curves when compared with ab initio generated GSFE curves. The MEAM parameters for element pairs were constructed based on the structural and elastic properties of element pairs in the NaCl reference structure garnered from ab initio calculations, with adjustment to reproduce the ab initio heat of formation of the most stable binary compounds. The new MEAM potentials were validated by comparing the formation energies of defects, equilibrium volumes, elastic moduli, and heat of formation for several binary compounds with ab initio simulations and experiments. Single elements in their ground-state crystal structure were subjected to heating to test the potentials at elevated temperatures. An Al potential was modified to avoid formation of an unphysical solid structure at high temperatures. The thermal expansion coefficient of a compound with the composition of AA 6061 alloy was evaluated and compared with experimental values. MEAM potential tests performed in this work, utilizing the universal atomistic simulation environment (ASE), are distributed to facilitate reproducibility of the results.

  • See Computed Properties
    Notes: This file was sent by Bohumir Jelinek (Mississippi State University) and posted on 3 July 2012. He noted, "This is a MEAM potential for Al, Si, Mg, Cu, Fe alloys. It works with LAMMPS, version 19 Jul 2011 or later, when compiled with MEAM support. Most of the MEAM potential results presented in the accompanying paper can be reproduced with Atomistic Simulation Environment (ASE) and testing routines are provided in ase-atomistic-potential-tests-rev60.tar.gz"
    File(s):
 
 
  • Citation: A. Gola, and L. Pastewka (2018), "Embedded atom method potential for studying mechanical properties of binary Cu–Au alloys", Modelling and Simulation in Materials Science and Engineering, 26(5), 055006. DOI: 10.1088/1361-651x/aabce4.
    Abstract: We present an embedded atom method (EAM) potential for the binary Cu–Au system. The unary phases are described by two well-tested unary EAM potentials for Cu and Au. We fitted the interaction between Cu and Au to experimental properties of the binary intermetallic phases Cu3Au, CuAu and CuAu3. Particular attention has been paid to reproducing stacking fault energies in order to obtain a potential suitable for studying deformation in this binary system. The resulting energies, lattice constant, elastic properties and melting points are in good agreement with available experimental data. We use nested sampling to show that our potential reproduces the phase boundaries between intermetallic phases and the disordered face-centered cubic solid solution. We benchmark our potential against four popular Cu–Au EAM parameterizations and density-functional theory calculations.

  • See Computed Properties
    Notes: Listing found at https://openkim.org.
    Link(s):
 
  • Citation: A. Agrawal, and R. Mirzaeifar (2021), "Copper-Graphene Composites; Developing the MEAM Potential and Investigating their Mechanical Properties", Computational Materials Science, 188, 110204. DOI: 10.1016/j.commatsci.2020.110204.
    Abstract: Unraveling the deformation mechanisms at the atomistic scale of metal matrix-graphene composites is a key step toward designing and fabricating these materials with exceptional mechanical properties. While these composites can be made by embedding graphene into multiple metallic matrices, it is shown that superior mechanical properties can be obtained by combining copper and graphene. In the past few years, molecular dynamics simulations have been used to investigate the fundamental deformation mechanisms at the nanoscale of Cu-graphene composites to facilitate designing these composites with improved mechanical properties. However, in all of the reported works, Lennard-Jones potential has been used for modeling the interaction between copper and carbon atoms. The complexities in the Cu-C interaction emerges the necessity of utilizing more accurate potentials. In this work, a 2NN MEAM (second nearest-neighbor modified embedded atomic method) potential for the copper and carbon atom interaction is developed. Since crystal structures like B1 or B2 are not experimentally available for the Cu-C system, first-principle calculations are used to determine the reference structure and its elastic constants in this work. It is shown that the B1 and B2 structure of Cu-C has positive formation energy, but B1 is dynamically stable. Accordingly, the B1 crystal structure is used as the reference structure for the Cu-C system to develop the interatomic potential. It is shown that the reported potential agrees reasonably well for phonon dispersion frequencies, stacking fault energies, and the atomic forces with the available experimental data and first-principle calculations. The developed potential is utilized to study the mechanical properties of copper-graphene composites subjected to uniaxial loading. Our results show that adding graphene to a defect-free Cu crystal weakens the metallic matrix’s mechanical properties. However, when the graphene is embedded into a Cu matrix with some defects, e.g., in a polycrystalline Cu, it can significantly improve the mechanical properties.

  • See Computed Properties
    Notes: These files were provided by Arpit Agrawal on August 26, 2021 and posted with his permission.
    File(s):
  • Citation: X.W. Zhou, D.K. Ward, and M.E. Foster (2015), "An analytical bond-order potential for carbon", Journal of Computational Chemistry, 36(23), 1719-1735. DOI: 10.1002/jcc.23949.
    Abstract: Carbon is the most widely studied material today because it exhibits special properties not seen in any other materials when in nano dimensions such as nanotube and graphene. Reduction of material defects created during synthesis has become critical to realize the full potential of carbon structures. Molecular dynamics (MD) simulations, in principle, allow defect formation mechanisms to be studied with high fidelity, and can, therefore, help guide experiments for defect reduction. Such MD simulations must satisfy a set of stringent requirements. First, they must employ an interatomic potential formalism that is transferable to a variety of carbon structures. Second, the potential needs to be appropriately parameterized to capture the property trends of important carbon structures, in particular, diamond, graphite, graphene, and nanotubes. Most importantly, the potential must predict the crystalline growth of the correct phases during direct MD simulations of synthesis to achieve a predictive simulation of defect formation. Because an unlimited number of structures not included in the potential parameterization are encountered, the literature carbon potentials are often not sufficient for growth simulations. We have developed an analytical bond order potential for carbon, and have made it available through the public MD simulation package LAMMPS. We demonstrate that our potential reasonably captures the property trends of important carbon phases. Stringent MD simulations convincingly show that our potential accounts not only for the crystalline growth of graphene, graphite, and carbon nanotubes but also for the transformation of graphite to diamond at high pressure.

    Notes: Notes from Dr. Zhou about the C-Cu interactions: "The C-Cu potential was constructed from the carbon potential (2015--Zhou-X-W-Ward-D-K-Foster-M-E--C) and Cu of the Al-Cu and Cu-H potentials (2016--Zhou-X-W-Ward-D-K-Foster-M-E--Al-Cu, 2015--Zhou-X-W-Ward-D-K-Foster-M-Zimmerman-J-A--Cu-H), except that a Morse potential is added to the Cu so that the cohesive energy of Cu is deliberately significantly increased but the lattice constant of Cu is unchanged. This allows simulations of growth of C on Cu to be performed at temperatures higher than the Cu melting temperature (to accelerate the simulations) without other negative consequencies."

  • See Computed Properties
    Notes: This file was taken from the August 22, 2018 LAMMPS distribution and listed as having been created by X.W. Zhou (Sandia)
    File(s):
 
  • Citation: O.R. Deluigi, R.C. Pasianot, F.J. Valencia, A. Caro, D. Farkas, and E.M. Bringa (2021), "Simulations of primary damage in a High Entropy Alloy: Probing enhanced radiation resistance", Acta Materialia, 213, 116951. DOI: 10.1016/j.actamat.2021.116951.
    Abstract: High Entropy Alloys (HEA) attract attention as possible radiation resistant materials, a feature observed in some experiments that has been attributed to several unique properties of HEA, in particular to the disorder-induced reduced thermal conductivity and to the peculiar defect properties originating from the chemical complexity. To explore the origin of such behavior we study the early stages (less than 0.1 ns), of radiation damage response of a HEA using molecular dynamics simulations of collision cascades induced by primary knock-on atoms (PKA) with 10, 20 and 40 keV, at room temperature, on an idealized model equiatomic quinary fcc FeNiCrCoCu alloy, the corresponding "Average Atom" (AA) material, and on pure Ni. We include accurate corrections to describe short-range atomic interactions during the cascade. In all cases the average number of defects in the HEA is lower than for pure Ni, which has been previously used to help claiming that HEA is radiation resistant. However, simulated defect evolution during primary damage, including the number of surviving Frenkel Pairs, and the defect cluster size distributions are nearly the same in all cases, within our statistical uncertainty. The number of surviving FP in the alloy is predicted fairly well by analytical models of defect production in pure materials. All of this indicates that the origin of radiation resistance in HEAs as observed in experiments may not be related to a reduction in primary damage due to chemical disorder, but is probably caused by longer-time defect evolution.

    Notes: This is a modified version of 2018--Farkas-D-Caro-A--Fe-Ni-Cr-Co-Cu that adds the ZBL correction at shorter interatomic distances making it suitable for radiation studies.

  • See Computed Properties
    Notes: This file was provided by Diana Farkas (Virginia Tech) on May 16, 2021 and posted with her permission.
    File(s):
 
 
 
 
 
  • Citation: X.W. Zhou, D.K. Ward, M. Foster, and J.A. Zimmerman (2015), "An analytical bond-order potential for the copper-hydrogen binary system", Journal of Materials Science, 50(7), 2859-2875. DOI: 10.1007/s10853-015-8848-9.
    Abstract: Despite extensive studies in the past, deterioration of mechanical properties due to hydrogen environment exposure remains a serious problem for structural materials. More effective improvement of a material’s resilience requires advanced computational methods to elucidate the fundamental mechanisms of the hydrogen effects. To enable accurate molecular dynamics (MD) studies of the hydrogen effects on metals, we have developed a high-fidelity analytical bond-order potential (BOP) for the copper–hydrogen binary system as a representative case. This potential is available through the publically available MD code LAMMPS. The potential parameters are optimized using an iterative process. First, the potential is fitted to static and reactive properties of a variety of elemental and binary configurations including small clusters and bulk lattices (with coordination varying from 1 to 12). Then the potential is put through a series of rigorous MD simulation tests (e.g., vapor deposition and solidification) that involve chaotic initial configurations. It is demonstrated that this Cu–H BOP not only gives structural and property trends close to those seen in experiments and quantum mechanical calculations, but also predicts the correct phase transformations and chemical reactions in direct MD simulations. The correct structural evolution from chaotic initial states strongly verifies the transferability of the potential. A highly transferable potential is the reason that a well-parameterized analytical BOP can enable MD simulations of metal-hydrogen interactions to reach a fidelity level not achieved in the past.

  • See Computed Properties
    Notes: This file was taken from the August 22, 2018 LAMMPS distribution and listed as having been created by X.W. Zhou (Sandia)
    File(s):
 
  • Citation: N.P. Bailey, J. Schiøtz, and K.W. Jacobsen (2004), "Simulation of Cu-Mg metallic glass: Thermodynamics and structure", Physical Review B, 69(14), 144205. DOI: 10.1103/physrevb.69.144205.
    Abstract: We have obtained effective medium theory interatomic potential parameters suitable for studying Cu-Mg metallic glasses. We present thermodynamic and structural results from simulations of such glasses over a range of compositions. We have produced low-temperature configurations by cooling from the melt at as slow a rate as practical, using constant temperature and pressure molecular dynamics. During the cooling process we have carried out thermodynamic analyses based on the temperature dependence of the enthalpy and its derivative, the specific heat, from which the glass transition temperature may be determined. We have also carried out structural analyses using the radial distribution function (RDF) and common neighbor analysis (CNA). Our analysis suggests that the splitting of the second peak, commonly associated with metallic glasses, in fact, has little to do with the glass transition itself, but is simply a consequence of the narrowing of peaks associated with structural features present in the liquid state. In fact, the splitting temperature for the Cu-Cu RDF is well above Tg. The CNA also highlights a strong similarity between the structure of the intermetallic alloys and the amorphous alloys of similar composition. We have also investigated the diffusivity in the supercooled regime. Its temperature dependence indicates fragile-liquid behavior, typical of binary metallic glasses. On the other hand, the relatively low specific-heat jump of around 1.5kB/atom indicates apparent strong-liquid behavior, but this can be explained by the width of the transition due to the high cooling rates.
    Citation: N.P. Bailey, J. Schiøtz, and K.W. Jacobsen (2017), "Erratum: Simulation of Cu-Mg metallic glass: Thermodynamics and structure [Phys. Rev. B \n69\n, 144205 (2004)]", Physical Review B, 96(5), 059904. DOI: 10.1103/physrevb.96.059904.

    Notes: This model implements a special parametrization optimized for CuMg bulk metallic glasses only! It probably gives reasonable results for other CuMg compounds.

 
 
  • Citation: A.S.M. Miraz, N. Dhariwal, W.J. Meng, B.R. Ramachandran, and C.D. Wick (2020), "Development and application of interatomic potentials to study the stability and shear strength of Ti/TiN and Cu/TiN interfaces", Materials & Design, 196, 109123. DOI: 10.1016/j.matdes.2020.109123.
    Abstract: A modified embedded atom method interatomic potential was developed to study semi-coherent metal/ceramic interfaces involving Cu, Ti and N. A genetic algorithm was used to fit the model parameters to the physical properties of the materials. To accurately describe interfacial interactions and shear, two-dimensional generalized stacking fault energy profiles for relevant slip systems were selected as one of the major parameterization targets for the models. The models were applied to study semi-coherent Ti(0001)/TiN(111) and Cu(111)/TiN(111) systems. Ti/TiN was stable with misfits accommodated away from the interface. Cu/TiN, in contrast, was more stable with misfits at the interface. A spiral pattern in the misfit dislocation networks was observed away from the Cu/TiN interface, similar to the metal/metal (111) semi-coherent interfaces. The theoretical shear strength calculated for Ti/TiN when the misfits were several layers away from the interface and for Cu/TiN with the misfit at the chemical interface, had reasonable agreement with experiment.

    Notes: Abu Shama M Miraz notes: "Our potential is mainly focused on the mechanical response of semi-coherent Ti/TiN and Cu/TiN metal/ceramic interfacial systems. We have separately parameterized to pure Cu and Ti first. So the models are good to use for these pure elements alone, if one wishes. Next, the binary Cu-Ti, Ti-N and Cu-N were fit to the model. And finally, the ternary Cu-Ti-N potential was fit to Cu/TiN metal/ceramic interfacial systems of different orientation relations. The properties that were fit can be found in the paper."

  • See Computed Properties
    Notes: These files were provided by Abu Shama M Miraz (Louisiana Tech) on Sept. 18, 2020 and posted with his permission.
    File(s):
 
  • Citation: B. Onat, and S. Durukanoğlu (2013), "An optimized interatomic potential for Cu–Ni alloys with the embedded-atom method", Journal of Physics: Condensed Matter, 26(3), 035404. DOI: 10.1088/0953-8984/26/3/035404.
    Abstract: We have developed a semi-empirical and many-body type model potential using a modified charge density profile for Cu–Ni alloys based on the embedded-atom method (EAM) formalism with an improved optimization technique. The potential is determined by fitting to experimental and first-principles data for Cu, Ni and Cu–Ni binary compounds, such as lattice constants, cohesive energies, bulk modulus, elastic constants, diatomic bond lengths and bond energies. The generated potentials were tested by computing a variety of properties of pure elements and the alloy of Cu, Ni: the melting points, alloy mixing enthalpy, lattice specific heat, equilibrium lattice structures, vacancy formation and interstitial formation energies, and various diffusion barriers on the (100) and (111) surfaces of Cu and Ni.

  • LAMMPS pair_style eam/alloy (2013--Onat-B--Cu-Ni--LAMMPS--ipr1)
    See Computed Properties
    Notes: This file was taken from the August 22, 2018 LAMMPS distribution.
    File(s): superseded


  • LAMMPS pair_style eam/alloy (2013--Onat-B--Cu-Ni--LAMMPS--ipr2)
    See Computed Properties
    Notes: This file was taken from openKIM model EAM_Dynamo_Onat_Durukanoglu_CuNi__MO_592013496703_004. It features more tabulation points and higher cutoffs for both rho and r.
    File(s):
  • See Computed Properties
    Notes: Listing found at https://openkim.org. This KIM potential is based on the same files as 2013--Onat-B--Cu-Ni--LAMMPS--ipr2.
    Link(s):
  • Citation: S.M. Foiles (1985), "Calculation of the surface segregation of Ni-Cu alloys with the use of the embedded-atom method", Physical Review B, 32(12), 7685-7693. DOI: 10.1103/physrevb.32.7685.
    Abstract: The surface composition of Ni-Cu alloys has been calculated as a function of atomic layer, crystal face, and bulk composition at a temperature of 800 K. The results show that the composition varies nonmonotonically near the surface with the surface layer strongly enriched in Cu while the near-surface layers are enriched in Ni. The calculations use the embedded-atom method [M. S. Daw and M. I. Baskes, Phys. Rev. B 29, 6443 (1984)] in conjunction with Monte Carlo computer simulations. The embedding functions and pair interactions needed to describe Ni-Cu alloys are developed and applied to the calculation of bulk energies, lattice constants, and short-range order. The heats of segregation are computed for the dilute limit, and the composition profile is obtained for the (100), (110), and (111) surfaces for a variety of bulk compositions. The results are found to be in accord with experimental data.

  • See Computed Properties
    Notes: These files were obtained from the December 9, 2007 LAMMPS distribution. According to Stephen M. Foiles, they differ from the original formulations in the following ways: a) The fcc is upper case in one and lower case in the other. b) The comment in the LAMMPS distribution for Ni_smf7.eam incorrectly lists it as being for the NiPd alloys rather than NiCu alloys. The potential file has been updated with "NiCu" to reflect the second comment.
    File(s):
  • See Computed Properties
    Notes: Listing found at https://openkim.org. This KIM potential is based on the Cu file from 1985--Foiles-S-M--Ni-Cu--LAMMPS--ipr1.
    Link(s):
  • See Computed Properties
    Notes: Listing found at https://openkim.org. This KIM potential is based on the Ni file from 1985--Foiles-S-M--Ni-Cu--LAMMPS--ipr1.
    Link(s):
 
 
 
 
  • Citation: A. Hashibon, A.Y. Lozovoi, Y. Mishin, C. Elsässer, and P. Gumbsch (2008), "Interatomic potential for the Cu-Ta system and its application to surface wetting and dewetting", Physical Review B, 77(9), 094131. DOI: 10.1103/physrevb.77.094131.
    Abstract: An angle-dependent interatomic potential has been developed for the Cu-Ta system by crossing two existing potentials for pure Cu and Ta. The cross-interaction functions have been fitted to first-principles data generated in this work. The potential has been extensively tested against first-principles energies not included in the fitting database and applied to molecular dynamics simulations of wetting and dewetting of Cu on Ta. We find that a Cu film placed on a Ta (110) surface dewets from it, forming a Cu droplet on top of a stable Cu monolayer. We also observe that a drop of liquid Cu placed on a clean Ta (110) surface spreads over it as a stable monolayer, while the extra Cu atoms remain in the drop. The stability of a Cu monolayer and instability of thicker Cu films are consistent with recent experiments and first-principles calculations. This agreement demonstrates the utility of the potential for atomistic simulations of Cu-Ta interfaces.

    Notes: Prof. Mishin requested the following be noted: There was a typing error in the original ADP paper (Y. Mishin, et al., Acta Mat. 53, 4029 (2005)). More information and a correction can be found in the FAQ. Update 17 Jan. 2014: Prof. Mishin noted that "Our ADP Ta potential has a known error: the elastic constants predicted by the potential as a factor of two different from those reported in the paper. This was the result of a bug in the fitting code that was used during the potential development. All other properties are exactly as reported in the paper. The mixed Cu-Ta interactions are also fine. However, because of this error in the elastic constants, the potential cannot be recommended for studying mechanical properties of pure Ta." Update: The 2015--Purja-Pun-G-P--Cu-Ta ADP potential has supplanted this potential.

  • ADP tabulated functions (2008--Hashibon-A--Cu-Ta--table--ipr1)
    Notes: These files were provided by Yuri Mishin (George Mason University) and posted on 22 Jan. 2010.
    File(s): superseded


  • Citation: X.W. Zhou, R.A. Johnson, and H.N.G. Wadley (2004), "Misfit-energy-increasing dislocations in vapor-deposited CoFe/NiFe multilayers", Physical Review B, 69(14), 144113. DOI: 10.1103/physrevb.69.144113.
    Abstract: Recent molecular dynamics simulations of the growth of [Ni0.8Fe0.2/Au] multilayers have revealed the formation of misfit-strain-reducing dislocation structures very similar to those observed experimentally. Here we report similar simulations showing the formation of edge dislocations near the interfaces of vapor-deposited (111) [NiFe/CoFe/Cu] multilayers. Unlike misfit dislocations that accommodate lattice mismatch, the dislocation structures observed here increase the mismatch strain energy. Stop-action observations of the dynamically evolving atomic structures indicate that during deposition on the (111) surface of a fcc lattice, adatoms may occupy either fcc sites or hcp sites. This results in the random formation of fcc and hcp domains, with dislocations at the domain boundaries. These dislocations enable atoms to undergo a shift from fcc to hcp sites, or vice versa. These shifts lead to missing atoms, and therefore a later deposited layer can have missing planes compared to a previously deposited layer. This dislocation formation mechanism can create tensile stress in fcc films. The probability that such dislocations are formed was found to quickly diminish under energetic deposition conditions.

  • FORTRAN (2004--Zhou-X-W--Ta-Cu--FORTRAN--ipr1)
    Notes: These are the original files sent by X.W. Zhou (Sandia National Laboratory) and posted with his permission. C.A. Becker (NIST) modified create.f to include the reference in the generated potential files and the EAM.input file for this composition. These files can be used to generate alloy potentials for Cu, Ag, Au, Ni, Pd, Pt, Al, Pb, Fe, Mo, Ta, W, Mg, Co, Ti, and Zr by editing EAM.input. However, as addressed in the reference, these potentials were not designed for use with metal compounds.
    File(s): superseded


  • LAMMPS pair_style eam/alloy (2004--Zhou-X-W--Ta-Cu--LAMMPS--ipr1)
    See Computed Properties
    Notes: This file was generated by C.A. Becker (NIST) from create.f and posted with X.W. Zhou's (Sandia National Laboratory) permission. The tabulations in this file are identical to the tabulations in the "CuTa.eam.alloy" file in the August 22, 2018 LAMMPS distribution.
    File(s): superseded


  • FORTRAN (2004--Zhou-X-W--Ta-Cu--FORTRAN--ipr2)
    Notes: The file Zhou04_create_v2.f is an updated version of create.f modified by L.M. Hale (NIST) following advice from X.W. Zhou (Sandia National Laboratory). This version removes spurious fluctuations in the tabulated functions of the original potential files caused by single/double precision floating point number conflicts.
    File(s):
  • LAMMPS pair_style eam/alloy (2004--Zhou-X-W--Ta-Cu--LAMMPS--ipr2)
    See Computed Properties
    Notes: This file was generated by L.M. Hale from Zhou04_create_v2.f on 13 April 2018 and posted with X.W. Zhou's (Sandia National Laboratory) permission. This version corrects an issue with spurious fluctuations in the tabulated functions.
    File(s):
  • See Computed Properties
    Notes: Listing found at https://openkim.org. This KIM potential is based on the files from 2004--Zhou-X-W--Ta-Cu--LAMMPS--ipr1.
    Link(s): superseded


  • See Computed Properties
    Notes: Listing found at https://openkim.org. This KIM potential is based on the files from 2004--Zhou-X-W--Ta-Cu--LAMMPS--ipr2.
    Link(s):
 
  • Citation: A. Clement, and T. Auger (2022), "An EAM potential for α-brass copper–zinc alloys: application to plasticity and fracture", Modelling and Simulation in Materials Science and Engineering, 31(1), 015004. DOI: 10.1088/1361-651x/aca4ec.
    Abstract: An embedded atom method potential has been developed for copper–zinc alloys valid from 0% to 37% zinc content (dedicated to describe the α fcc phase). It has been fit to a set of first-principles data for the fcc copper, the fcc Cu3Zn DO23 phase and Zn on a fcc lattice. Elastic anisotropies, the lattice parameter, cohesive energy are used as input. Ponctual defects, surface energies, intrinsic stacking fault and phonon spectrum have been computed and compare well with experimental trends. This potential has been used to study dislocation dissociation and dislocation emission at a crack tip up to 30% Zn. Dislocation emission at the crack tip is correctly described compared with recent parametrization including the surface energy. It is found that with alloying, dislocation emission becomes easier following the decrease of the unstable stacking fault energy with Zn concentration, a non-trivial finding. This potential is therefore well suited to carry out basic studies of plasticity and fracture in α-brass alloys.

    Notes: This potential can be used to model copper and zinc in fcc phase, as well as the alpha-brass alloy up to 35% of zinc. This potential was developed for the alpha-brass alloys only and should not be used with higher zinc concentration.

  • LAMMPS pair_style eam/alloy (2022--Clement-A--Cu-Zn--LAMMPS--ipr1)
    See Computed Properties
    Notes: This file was provided by Antoine Clement on 3 April 2023.
    File(s):
 
  • Citation: N. Leimeroth, J. Rohrer, and K. Albe (2024), "General purpose potential for glassy and crystalline phases of Cu-Zr alloys based on the ACE formalism", Physical Review Materials, 8(4), 043602. DOI: 10.1103/physrevmaterials.8.043602.
    Abstract: A general purpose machine-learning interatomic potential (MLIP) for the Cu-Zr system is presented based on the atomic cluster expansion formalism [R. Drautz, Phys. Rev. B 99, 014104 (2019)]. By using an extensive set of Cu-Zr training data generated withdensity functional theory, this potential describes a wide range of properties of crystalline as well as amorphous phases within the whole compositional range. Therefore, the machine learning interatomic potential (MLIP) can reproduce the experimental phase diagram and amorphous structure with considerably improved accuracy. A massively different short-range order compared to classica interatomic potentials is found in glassy Cu-Zr samples, shedding light on the role of the full icosahedral motif in the material. Tensile tests of B2-CuZr inclusions in an Cu50⁢Zr50 amorphous matrix reveal the occurrence of martensitic phase transformations in this crystal-glass nanocomposite.

    Notes: This potential was designed to model both glassy and crystalline phases across the whole compositional range.

  • See Computed Properties
    Notes: These files were provided by Niklas Leimeroth on October 23, 2024.
    File(s): Link(s):
  • Citation: A. Pǎduraru, A. Kenoufi, N.P. Bailey, and J. Schiøtz (2007), "An Interatomic Potential for Studying CuZr Bulk Metallic Glasses", Advanced Engineering Materials, 9(6), 505-508. DOI: 10.1002/adem.200700047.
    Abstract: Glass forming ability has been found in only a small number of binary alloys, one being CuZr. In order to simulate this glass, we fitted an interatomic potential within Effective Medium Theory (EMT). For this purpose we use basic properties of the B2 crystal structure as calculated from Density Functional Theory (DFT) or obtained from experiments. We then performed Molecular Dynamics (MD) simulations of the cooling process and studied the thermodynamics and structure of CuZr glass. We find that the potential gives a good description of the CuZr glass, with a glass transition temperature and elastic constants close to the experimental values. The local atomic order, as witnessed by the radial distribution function, is also consistent with similar experimental data.

    Notes: This model implements a special parametrization optimized for CuZr bulk metallic glasses only! It probably gives reasonable results for other CuZr compounds.

 
  • Citation: V. Borovikov, M.I. Mendelev, and A.H. King (2016), "Effects of stable and unstable stacking fault energy on dislocation nucleation in nano-crystalline metals", Modelling and Simulation in Materials Science and Engineering, 24(8), 085017. DOI: 10.1088/0965-0393/24/8/085017.
    Abstract: Dislocation nucleation from grain boundaries (GB) can control plastic deformation in nano-crystalline metals under certain conditions, but little is known about what controls dislocation nucleation, because when data from different materials are compared, the variations of many interacting properties tend to obscure the effects of any single property. In this study, we seek clarification by applying a unique capability of semi-empirical potentials in molecular dynamics simulations: the potentials can be modified such that all significant material properties but one, are kept constant. Using a set of potentials developed to isolate the effects of stacking fault energy, we show that for a given grain boundary, loading orientation and strain rate, the yield stress depends linearly on both the stable and unstable stacking fault energies. The coefficients of proportionality depend on the GB structure and the value of the yield stress is related to the density of the E structural units in the GB. While the impact of the stable stacking fault energy is easy to understand, the unstable stacking fault energy requires more elucidation and we provide a framework for understanding how it affects the nucleation and propagation process.

    Notes: This listing is for the MCu31 parameterization listed in the reference. Dr. M.I. Mendelev (Ames Laboratory) noted that these are new fictional potentials intended to supplement the existing potentials posted to the NIST repository (as the 2015--Borovikov-V-Mendelev-M-I-King-A-H-LeSar-R--fictional-Cu-# listings). Dr. Mendelev further noted that, "the new potentials provide the same SFE as 2013--Mendelev-M-I-King-A-H--Cu but different unstable stacking fault energy (USFE). All these Cu fictional potentials are designed to study the effect of SFE and USFE on the deformation behavior in fcc metals." Reference information added March 5, 2020.

  • See Computed Properties
    Notes: This file was sent by M.I. Mendelev (Ames Laboratory) on 19 Aug. 2015 and posted with his permission. Update 19 July 2021: The contact email in the file's header has been changed. Update Jan 14 2022: Citation information has been updated in the file's header.
    File(s):
  • Citation: V. Borovikov, M.I. Mendelev, and A.H. King (2016), "Effects of stable and unstable stacking fault energy on dislocation nucleation in nano-crystalline metals", Modelling and Simulation in Materials Science and Engineering, 24(8), 085017. DOI: 10.1088/0965-0393/24/8/085017.
    Abstract: Dislocation nucleation from grain boundaries (GB) can control plastic deformation in nano-crystalline metals under certain conditions, but little is known about what controls dislocation nucleation, because when data from different materials are compared, the variations of many interacting properties tend to obscure the effects of any single property. In this study, we seek clarification by applying a unique capability of semi-empirical potentials in molecular dynamics simulations: the potentials can be modified such that all significant material properties but one, are kept constant. Using a set of potentials developed to isolate the effects of stacking fault energy, we show that for a given grain boundary, loading orientation and strain rate, the yield stress depends linearly on both the stable and unstable stacking fault energies. The coefficients of proportionality depend on the GB structure and the value of the yield stress is related to the density of the E structural units in the GB. While the impact of the stable stacking fault energy is easy to understand, the unstable stacking fault energy requires more elucidation and we provide a framework for understanding how it affects the nucleation and propagation process.

    Notes: This listing is for the MCu32 parameterization listed in the reference. Dr. M.I. Mendelev (Ames Laboratory) noted that these are new fictional potentials intended to supplement the existing potentials posted to the NIST repository (as the 2015--Borovikov-V-Mendelev-M-I-King-A-H-LeSar-R--fictional-Cu-# listings). Dr. Mendelev further noted that, "the new potentials provide the same SFE as 2013--Mendelev-M-I-King-A-H--Cu but different unstable stacking fault energy (USFE). All these Cu fictional potentials are designed to study the effect of SFE and USFE on the deformation behavior in fcc metals." Reference information added March 5, 2020.

  • See Computed Properties
    Notes: This file was sent by M.I. Mendelev (Ames Laboratory) on 19 Aug. 2015 and posted with his permission. Update 19 July 2021: The contact email in the file's header has been changed. Update Jan 14 2022: Citation information has been updated in the file's header.
    File(s):
  • Citation: V. Borovikov, M.I. Mendelev, and A.H. King (2016), "Effects of stable and unstable stacking fault energy on dislocation nucleation in nano-crystalline metals", Modelling and Simulation in Materials Science and Engineering, 24(8), 085017. DOI: 10.1088/0965-0393/24/8/085017.
    Abstract: Dislocation nucleation from grain boundaries (GB) can control plastic deformation in nano-crystalline metals under certain conditions, but little is known about what controls dislocation nucleation, because when data from different materials are compared, the variations of many interacting properties tend to obscure the effects of any single property. In this study, we seek clarification by applying a unique capability of semi-empirical potentials in molecular dynamics simulations: the potentials can be modified such that all significant material properties but one, are kept constant. Using a set of potentials developed to isolate the effects of stacking fault energy, we show that for a given grain boundary, loading orientation and strain rate, the yield stress depends linearly on both the stable and unstable stacking fault energies. The coefficients of proportionality depend on the GB structure and the value of the yield stress is related to the density of the E structural units in the GB. While the impact of the stable stacking fault energy is easy to understand, the unstable stacking fault energy requires more elucidation and we provide a framework for understanding how it affects the nucleation and propagation process.

    Notes: This listing is for the MCu33 parameterization listed in the reference. Dr. M.I. Mendelev (Ames Laboratory) noted that these are new fictional potentials intended to supplement the existing potentials posted to the NIST repository (as the 2015--Borovikov-V-Mendelev-M-I-King-A-H-LeSar-R--fictional-Cu-# listings). Dr. Mendelev further noted that, "the new potentials provide the same SFE as 2013--Mendelev-M-I-King-A-H--Cu but different unstable stacking fault energy (USFE). All these Cu fictional potentials are designed to study the effect of SFE and USFE on the deformation behavior in fcc metals." Reference information added March 5, 2020.

  • See Computed Properties
    Notes: This file was sent by M.I. Mendelev (Ames Laboratory) on 19 Aug. 2015 and posted with his permission. Update 19 July 2021: The contact email in the file's header has been changed. Update Jan 14 2022: Citation information has been updated in the file's header.
    File(s):
  • Citation: V. Borovikov, M.I. Mendelev, and A.H. King (2016), "Effects of stable and unstable stacking fault energy on dislocation nucleation in nano-crystalline metals", Modelling and Simulation in Materials Science and Engineering, 24(8), 085017. DOI: 10.1088/0965-0393/24/8/085017.
    Abstract: Dislocation nucleation from grain boundaries (GB) can control plastic deformation in nano-crystalline metals under certain conditions, but little is known about what controls dislocation nucleation, because when data from different materials are compared, the variations of many interacting properties tend to obscure the effects of any single property. In this study, we seek clarification by applying a unique capability of semi-empirical potentials in molecular dynamics simulations: the potentials can be modified such that all significant material properties but one, are kept constant. Using a set of potentials developed to isolate the effects of stacking fault energy, we show that for a given grain boundary, loading orientation and strain rate, the yield stress depends linearly on both the stable and unstable stacking fault energies. The coefficients of proportionality depend on the GB structure and the value of the yield stress is related to the density of the E structural units in the GB. While the impact of the stable stacking fault energy is easy to understand, the unstable stacking fault energy requires more elucidation and we provide a framework for understanding how it affects the nucleation and propagation process.

    Notes: This listing is for the MCu34 parameterization listed in the reference. Dr. M.I. Mendelev (Ames Laboratory) noted that these are new fictional potentials intended to supplement the existing potentials posted to the NIST repository (as the 2015--Borovikov-V-Mendelev-M-I-King-A-H-LeSar-R--fictional-Cu-# listings). Dr. Mendelev further noted that, "the new potentials provide the same SFE as 2013--Mendelev-M-I-King-A-H--Cu but different unstable stacking fault energy (USFE). All these Cu fictional potentials are designed to study the effect of SFE and USFE on the deformation behavior in fcc metals." Reference information added March 5, 2020.

  • See Computed Properties
    Notes: This file was sent by M.I. Mendelev (Ames Laboratory) on 19 Aug. 2015 and posted with his permission. Update 19 July 2021: The contact email in the file's header has been changed. Update Jan 14 2022: Citation information has been updated in the file's header.
    File(s):
  • Citation: V. Borovikov, M.I. Mendelev, A.H. King, and R. LeSar (2015), "Effect of stacking fault energy on mechanism of plastic deformation in nanotwinned FCC metals", Modelling and Simulation in Materials Science and Engineering, 23(5), 055003. DOI: 10.1088/0965-0393/23/5/055003.
    Abstract: Starting from a semi-empirical potential designed for Cu, we have developed a series of potentials that provide essentially constant values of all significant (calculated) materials properties except for the intrinsic stacking fault energy, which varies over a range that encompasses the lowest and highest values observed in nature. These potentials were employed in molecular dynamics (MD) simulations to investigate how stacking fault energy affects the mechanical behavior of nanotwinned face-centered cubic (FCC) materials. The results indicate that properties such as yield strength and microstructural stability do not vary systematically with stacking fault energy, but rather fall into two distinct regimes corresponding to 'low' and 'high' stacking fault energies.

    Notes: This listing is for the MCu1 parameterization listed in the reference. The reference information was updated on 13 June 2015. Dr. Mendelev noted that these "are fictional potentials. MCu3 is a realistic potential for Cu; it is the same as 2013--Mendelev-M-I-King-A-H--Cu The rest of potentials were developed using exactly the same fitting procedure except of the target value for the stacking fault energy (SFE) which was varied. The potentials are designed to study the effect of SFE on the mechanical behavior of fcc metals. I also attached a table with the some properties by these potentials." The table is in PotentialProperties_MCu.pdf.

  • See Computed Properties
    Notes: These files were sent by M.I. Mendelev (Ames Laboratory) on 24 Nov. 2014 and posted with his permission. A corrected file for MCu1_MendelevM_2014.eam.fs was sent by M.I. Mendelev (Ames Laboratory) on 07 Oct. 2015, and the file has been replaced. It was determined that MCu2_MendelevM_2014.eam.fs was incidentally saved as MCu1_MendelevM_2014.eam.fs. Update 19 July 2021: The contact email in the file's header has been changed. Update Jan 14 2022: Citation information has been updated in the file's header.
    File(s):
  • Citation: V. Borovikov, M.I. Mendelev, A.H. King, and R. LeSar (2015), "Effect of stacking fault energy on mechanism of plastic deformation in nanotwinned FCC metals", Modelling and Simulation in Materials Science and Engineering, 23(5), 055003. DOI: 10.1088/0965-0393/23/5/055003.
    Abstract: Starting from a semi-empirical potential designed for Cu, we have developed a series of potentials that provide essentially constant values of all significant (calculated) materials properties except for the intrinsic stacking fault energy, which varies over a range that encompasses the lowest and highest values observed in nature. These potentials were employed in molecular dynamics (MD) simulations to investigate how stacking fault energy affects the mechanical behavior of nanotwinned face-centered cubic (FCC) materials. The results indicate that properties such as yield strength and microstructural stability do not vary systematically with stacking fault energy, but rather fall into two distinct regimes corresponding to 'low' and 'high' stacking fault energies.

    Notes: This listing is for the MCu2 parameterization listed in the reference. The reference information was updated on 13 June 2015. Dr. Mendelev noted that these "are fictional potentials. MCu3 is a realistic potential for Cu; it is the same as 2013--Mendelev-M-I-King-A-H--Cu The rest of potentials were developed using exactly the same fitting procedure except of the target value for the stacking fault energy (SFE) which was varied. The potentials are designed to study the effect of SFE on the mechanical behavior of fcc metals. I also attached a table with the some properties by these potentials." The table is in PotentialProperties_MCu.pdf.

  • See Computed Properties
    Notes: These files were sent by M.I. Mendelev (Ames Laboratory) on 24 Nov. 2014 and posted with his permission. Update 19 July 2021: The contact email in the file's header has been changed. Update Jan 14 2022: Citation information has been updated in the file's header.
    File(s):
  • Citation: V. Borovikov, M.I. Mendelev, A.H. King, and R. LeSar (2015), "Effect of stacking fault energy on mechanism of plastic deformation in nanotwinned FCC metals", Modelling and Simulation in Materials Science and Engineering, 23(5), 055003. DOI: 10.1088/0965-0393/23/5/055003.
    Abstract: Starting from a semi-empirical potential designed for Cu, we have developed a series of potentials that provide essentially constant values of all significant (calculated) materials properties except for the intrinsic stacking fault energy, which varies over a range that encompasses the lowest and highest values observed in nature. These potentials were employed in molecular dynamics (MD) simulations to investigate how stacking fault energy affects the mechanical behavior of nanotwinned face-centered cubic (FCC) materials. The results indicate that properties such as yield strength and microstructural stability do not vary systematically with stacking fault energy, but rather fall into two distinct regimes corresponding to 'low' and 'high' stacking fault energies.

    Notes: This listing is for the MCu3 parameterization listed in the reference. The reference information was updated on 13 June 2015. Dr. Mendelev noted that these "are fictional potentials. MCu3 is a realistic potential for Cu; it is the same as 2013--Mendelev-M-I-King-A-H--Cu The rest of potentials were developed using exactly the same fitting procedure except of the target value for the stacking fault energy (SFE) which was varied. The potentials are designed to study the effect of SFE on the mechanical behavior of fcc metals. I also attached a table with the some properties by these potentials." The table is in PotentialProperties_MCu.pdf.

  • See Computed Properties
    Notes: These files were sent by M.I. Mendelev (Ames Laboratory) on 24 Nov. 2014 and posted with his permission. Update 19 July 2021: The contact email in the file's header has been changed. Update Jan 14 2022: Citation information has been updated in the file's header.
    File(s):
  • Citation: V. Borovikov, M.I. Mendelev, A.H. King, and R. LeSar (2015), "Effect of stacking fault energy on mechanism of plastic deformation in nanotwinned FCC metals", Modelling and Simulation in Materials Science and Engineering, 23(5), 055003. DOI: 10.1088/0965-0393/23/5/055003.
    Abstract: Starting from a semi-empirical potential designed for Cu, we have developed a series of potentials that provide essentially constant values of all significant (calculated) materials properties except for the intrinsic stacking fault energy, which varies over a range that encompasses the lowest and highest values observed in nature. These potentials were employed in molecular dynamics (MD) simulations to investigate how stacking fault energy affects the mechanical behavior of nanotwinned face-centered cubic (FCC) materials. The results indicate that properties such as yield strength and microstructural stability do not vary systematically with stacking fault energy, but rather fall into two distinct regimes corresponding to 'low' and 'high' stacking fault energies.

    Notes: This listing is for the MCu4 parameterization listed in the reference. The reference information was updated on 13 June 2015. Dr. Mendelev noted that these "are fictional potentials. MCu3 is a realistic potential for Cu; it is the same as 2013--Mendelev-M-I-King-A-H--Cu The rest of potentials were developed using exactly the same fitting procedure except of the target value for the stacking fault energy (SFE) which was varied. The potentials are designed to study the effect of SFE on the mechanical behavior of fcc metals. I also attached a table with the some properties by these potentials." The table is in PotentialProperties_MCu.pdf.

  • See Computed Properties
    Notes: These files were sent by M.I. Mendelev (Ames Laboratory) on 24 Nov. 2014 and posted with his permission. Update 19 July 2021: The contact email in the file's header has been changed. Update Jan 14 2022: Citation information has been updated in the file's header.
    File(s):
  • Citation: V. Borovikov, M.I. Mendelev, A.H. King, and R. LeSar (2015), "Effect of stacking fault energy on mechanism of plastic deformation in nanotwinned FCC metals", Modelling and Simulation in Materials Science and Engineering, 23(5), 055003. DOI: 10.1088/0965-0393/23/5/055003.
    Abstract: Starting from a semi-empirical potential designed for Cu, we have developed a series of potentials that provide essentially constant values of all significant (calculated) materials properties except for the intrinsic stacking fault energy, which varies over a range that encompasses the lowest and highest values observed in nature. These potentials were employed in molecular dynamics (MD) simulations to investigate how stacking fault energy affects the mechanical behavior of nanotwinned face-centered cubic (FCC) materials. The results indicate that properties such as yield strength and microstructural stability do not vary systematically with stacking fault energy, but rather fall into two distinct regimes corresponding to 'low' and 'high' stacking fault energies.

    Notes: This listing is for the MCu5 parameterization listed in the reference. The reference information was updated on 13 June 2015. Dr. Mendelev noted that these "are fictional potentials. MCu3 is a realistic potential for Cu; it is the same as 2013--Mendelev-M-I-King-A-H--Cu The rest of potentials were developed using exactly the same fitting procedure except of the target value for the stacking fault energy (SFE) which was varied. The potentials are designed to study the effect of SFE on the mechanical behavior of fcc metals. I also attached a table with the some properties by these potentials." The table is in PotentialProperties_MCu.pdf.

  • See Computed Properties
    Notes: These files were sent by M.I. Mendelev (Ames Laboratory) on 24 Nov. 2014 and posted with his permission. Update 19 July 2021: The contact email in the file's header has been changed. Update Jan 14 2022: Citation information has been updated in the file's header.
    File(s):
  • Citation: V. Borovikov, M.I. Mendelev, A.H. King, and R. LeSar (2015), "Effect of stacking fault energy on mechanism of plastic deformation in nanotwinned FCC metals", Modelling and Simulation in Materials Science and Engineering, 23(5), 055003. DOI: 10.1088/0965-0393/23/5/055003.
    Abstract: Starting from a semi-empirical potential designed for Cu, we have developed a series of potentials that provide essentially constant values of all significant (calculated) materials properties except for the intrinsic stacking fault energy, which varies over a range that encompasses the lowest and highest values observed in nature. These potentials were employed in molecular dynamics (MD) simulations to investigate how stacking fault energy affects the mechanical behavior of nanotwinned face-centered cubic (FCC) materials. The results indicate that properties such as yield strength and microstructural stability do not vary systematically with stacking fault energy, but rather fall into two distinct regimes corresponding to 'low' and 'high' stacking fault energies.

    Notes: This listing is for the MCu6 parameterization listed in the reference. The reference information was updated on 13 June 2015. Dr. Mendelev noted that these "are fictional potentials. MCu3 is a realistic potential for Cu; it is the same as 2013--Mendelev-M-I-King-A-H--Cu The rest of potentials were developed using exactly the same fitting procedure except of the target value for the stacking fault energy (SFE) which was varied. The potentials are designed to study the effect of SFE on the mechanical behavior of fcc metals. I also attached a table with the some properties by these potentials." The table is in PotentialProperties_MCu.pdf.

  • See Computed Properties
    Notes: These files were sent by M.I. Mendelev (Ames Laboratory) on 24 Nov. 2014 and posted with his permission. Update 19 July 2021: The contact email in the file's header has been changed. Update Jan 14 2022: Citation information has been updated in the file's header.
    File(s):
  • Citation: V. Borovikov, M.I. Mendelev, A.H. King, and R. LeSar (2015), "Effect of stacking fault energy on mechanism of plastic deformation in nanotwinned FCC metals", Modelling and Simulation in Materials Science and Engineering, 23(5), 055003. DOI: 10.1088/0965-0393/23/5/055003.
    Abstract: Starting from a semi-empirical potential designed for Cu, we have developed a series of potentials that provide essentially constant values of all significant (calculated) materials properties except for the intrinsic stacking fault energy, which varies over a range that encompasses the lowest and highest values observed in nature. These potentials were employed in molecular dynamics (MD) simulations to investigate how stacking fault energy affects the mechanical behavior of nanotwinned face-centered cubic (FCC) materials. The results indicate that properties such as yield strength and microstructural stability do not vary systematically with stacking fault energy, but rather fall into two distinct regimes corresponding to 'low' and 'high' stacking fault energies.

    Notes: This listing is for the MCu7 parameterization listed in the reference. The reference information was updated on 13 June 2015. Dr. Mendelev noted that these "are fictional potentials. MCu3 is a realistic potential for Cu; it is the same as 2013--Mendelev-M-I-King-A-H--Cu The rest of potentials were developed using exactly the same fitting procedure except of the target value for the stacking fault energy (SFE) which was varied. The potentials are designed to study the effect of SFE on the mechanical behavior of fcc metals. I also attached a table with the some properties by these potentials." The table is in PotentialProperties_MCu.pdf.

  • See Computed Properties
    Notes: These files were sent by M.I. Mendelev (Ames Laboratory) on 24 Nov. 2014 and posted with his permission. Update 19 July 2021: The contact email in the file's header has been changed. Update Jan 14 2022: Citation information has been updated in the file's header.
    File(s):
Date Created: October 5, 2010 | Last updated: October 29, 2024