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Citation: G.D. Samolyuk, L.K. Béland, G.M. Stocks, and R.E. Stoller (2016), "Electron–phonon coupling in Ni-based binary alloys with application to displacement cascade modeling", Journal of Physics: Condensed Matter, 28(17), 175501. DOI: 10.1088/0953-8984/28/17/175501.
Abstract: Energy transfer between lattice atoms and electrons is an important channel of energy dissipation during displacement cascade evolution in irradiated materials. On the assumption of small atomic displacements, the intensity of this transfer is controlled by the strength of electron–phonon (el–ph) coupling. The el–ph coupling in concentrated Ni-based alloys was calculated using electronic structure results obtained within the coherent potential approximation. It was found that Ni0.5Fe0.5, Ni0.5Co0.5 and Ni0.5Pd0.5 are ordered ferromagnetically, whereas Ni0.5Cr0.5 is nonmagnetic. Since the magnetism in these alloys has a Stoner-type origin, the magnetic ordering is accompanied by a decrease of electronic density of states at the Fermi level, which in turn reduces the el–ph coupling. Thus, the el–ph coupling values for all alloys are approximately 50% smaller in the magnetic state than for the same alloy in a nonmagnetic state. As the temperature increases, the calculated coupling initially increases. After passing the Curie temperature, the coupling decreases. The rate of decrease is controlled by the shape of the density of states above the Fermi level. Introducing a two-temperature model based on these parameters in 10 keV molecular dynamics cascade simulation increases defect production by 10–20% in the alloys under consideration.

Notes: Prof. Beland notes that "The potential takes elemental Ni from 2004--Mishin-Y--Ni-Al and Pd from 2011 Sheng and mixes them. We first applied the effective gauge transformation, and then fitted the cross-term as to reproduce the heat of mixing of Ni(x)-Pd(1-x). The potential is stiffened at short distances by following the procedure detailed in https://doi.org/10.1016/j.cpc.2017.05.001 and https://doi.org/10.1021/acs.jctc.5b01194".

LAMMPS pair_style eam/alloy (2016--Samolyuk-G-D--Ni-Pd--LAMMPS--ipr1)
See Computed Properties
Notes: This file was provided by Laurent Béland on 7 Nov 2019 and posted with his permission.
Date Created: October 5, 2010 | Last updated: July 09, 2021