Electronic structure

The following shows the electronic density of states and bandstructure. 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. Total DOS, Orbital DOS and Element dos buttons are provided for density of states options. Energy is rescaled to make Fermi-energy zero. In the bandstructure plot, spin up is 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): 0.0028I

Total DOS Orbital DOS Element DOS

Optical properties Semi-local

Incident photon energy dependence of optical is shown below. 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 layered materials needs to be rescaled with the actual thickness to simulation z-box ratio. Absorption coeffiecient is in cm-1 unit.

Dense k-mesh based bandgap is : 0.000200000000001 eV

Optical properties METAGGA-MBJ

Single point DFT calculation was carried out with meta-gga MBJ functional. This should give reasonable bandgap, and optical properties assuming the calculation was properly converged. Incident photon energy dependence of optical is shown below. Only interband optical transitions are taken into account.

MBJ bandgap is : 0.003 eV

Elastic tensor and derived phonon properties

Elastic tensor calculated for the conventional cell of the system with finite-difference method. For layered materials, the elastic constants are rescaled with respect to vacuum padding (see the input files) and the units for elastic coefficients are in N/m. Phonons obtained from this calcuation are also shown.

WARNING: Please note this may not be the exact phonon modes of the system as we did not test the cell-size dependence of phonons yet. At least 1.2 nm x1.2 nm x1.2 nm or more is needed for obtaining reliable phonon spectrum. For systems having primitive-cell phonon representation tables, I denotes infrared activity and R denotes Raman active modes (where applicabale). The minimum thermal conductivity was calculated using elastic tensor information following Clarke and Cahill formalism.

Bulk Modulus B_V 85.978 GPa

Shear Modulus G_V 23.347 GPa

Point group

point_group_type: 4/mmm

Visualize Phonons here

Phonon mode (cm-1)	Representation
-0.2936152138	A2u I
-0.1854294032	Eu I
67.7497378934	A2u I
69.0041283335	Eu I
252.901943464	Eg R
253.149973092	B1g R
261.414435445	Eu I
261.925109179	A2u I