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): 3.2474D

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 : 3.2738 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 : 5.5393 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 7.4 GPa

Shear Modulus G_V -2.16 GPa

Point group

point_group_type: 4/mmm

Visualize Phonons here

Phonon mode (cm-1)	Representation
-254.984891569	A2g
-252.862092027	Eg R
-251.293401576	B1g R
-248.010069026	B1u
-245.965914953	Eu I
-244.119689197	A2u I
-134.802253352	B2u
-132.917582569	A1g R
-130.983894819	Eu I
-129.390457124	Eg R
-125.626401032	A1u
-123.876772576	B2g R
-24.8201725068	A2g
-20.0623789846	B1u
-19.3901179571	A1u
-14.0017511193	B1g R
0.0358285484	A2u I
0.0492507083	Eu I
19.098168751	Eg R
33.9078314903	B2g R
37.3826321914	Eu I
37.5064934302	Eg R
51.8733110604	B1g R
52.9862068711	A2u I
54.1910607044	B2u
55.4788133689	Eu I
56.1553218656	A2g
57.8568008403	B1u
62.4360794341	Eg R
67.5055749007	A1g R
852.015523712	A1u
853.348235906	B2g R
853.735564144	Eu I
854.824243164	Eg R
855.882839544	B2u
856.773179155	A1g R