| JARVIS-ID:JVASP-29967 | Functional:optB88-vdW | Primitive cell | Primitive cell | Conventional cell | Conventional cell |
| Chemical formula:Bi2PbSe4 | Formation energy/atom (eV):-0.458 | a 13.528 Å | α:18.037 ° | a 4.241 Å | α:90.0 ° |
| Space-group :R-3m, 166 | Relaxed energy/atom (eV):-1.9055 | b 13.528 Å | β:18.037 ° | b 4.241 Å | β:90.0 ° |
| Calculation type:Bulk | SCF bandgap (eV):0.444 | c 13.528 Å | γ:18.037 ° | c 39.914 Å | γ:120.0 ° |
| Crystal system:trigonal | Point group:-3m | Density (gcm-3):7.54 | Volume (Å3):207.25 | nAtoms_prim:7 | nAtoms_conv:21 |
The following shows the X-ray diffraction (XRD)[Source-code] pattern and the Radial distribution function (RDF) plots [Source-code]. XRD peaks should be comparable to experiments for bulk structures. Relative intensities may differ. For mono- and multi-layer structures , we take the z-dimension during DFT calculation for XRD calculations, which may differ from the experimental set-up.
The following shows the electronic density of states and bandstructure [Source-code]. DFT is generally predicted to underestimate bandgap of materials. Accurate band-gaps are obtained with higher level methods (with high computational requirement) such as HSE, GW , which are under progress. If available, MBJ data should be comparable to experiments also. Total DOS, Orbital DOS and Element dos [Source-code] buttons are provided for density of states options. Energy is rescaled to make Fermi-energy zero. In the bandstructure plot [Source-code], spin up is shown with blue lines while spin down are shown with red lines. Non-degenerate spin-up and spin-down states (if applicable) would imply a net orbital magnetic moment in the system. Fermi-occupation tolerance for bandgap calculation is chosen as 0.001.
High-symmetry kpoints based bandgap (eV): 0.241D
The following plot shows the plane averaged electrostatic potential (ionic+Hartree) along x, y and z-directions. The red line shows the Fermi-energy while the green line shows the maximum value of the electrostatic potential. For slab structures (with vacuum along z-direction), the difference in these two values can be used to calculate work-function of the material.
Exfoliation energy (meV/atom) is: 48.72
Below we show results from spin-orbit coupling (SOC) based spillage calculations using wavefunctions of spin-orbit and non-spin-orbit bandstructure calculations. a) non-SOC band structure and b) SOC band structure, c) non-SOC projected band structure and d) SOC projected band structure, projecting onto highest energy orbital of most electronegative atom in the system (assuming the orbital forms the valence band-maximum). e) Spillage, as a function of momentum, k. f) Table of bandgaps and spillage information. Generally, spillage values greater than 0.5 and indirect gap close to zero indicate topological materials.
Spin-orbit spillage is: 2.165
Incident photon energy dependence of optical is shown below [Source-code]. Only interband optical transitions are taken into account.Please note the underestimatation of band-gap problem with DFT will reflect in the spectra as well. For very accurate optical properties GW/BSE calculation would be needed, which is yet to be done because of their very high computational cost. Optical properties for mono-/multi-layer materials were rescaled with the actual thickness to simulation z-box ratio. Absorption coeffiecient is in cm-1 unit. Also, ionic contributions were neglected.
Dense k-mesh based bandgap is : 0.4442 eV
Static real-parts of dielectric function in x,y,z: 21.43,21.44,20.75
Calculations are done using density functional perturbation theory (DFPT) method for non-metallic systems for conventional cell and at Gamma-point in phonon BZ.
| 96.41 | 0.0 | -0.0 |
| 0.0 | 96.41 | 0.0 |
| -0.0 | 0.0 | 25.12 |
| -0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 |
| -0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 |
| -0.0 | -0.0 | -0.0 | 0.0 | 0.0 | 0.0 |
Links to other databases or papers are provided below
mp-675543