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Structural formula: Sn1 Ge1

Functional: optB88-vDW

Space group : P1

Calculation type: Bulk

JARVIS ID: JVASP-30502

Formation energy/atom (eV): 0.584

Relaxed energy/atom (eV): -0.2271

Primitive cell lattice parameters

a 4.438 Å , b 4.434 Å , c 6.723 Å

α 90.114 ° , β 89.94 ° , γ 120.139 °

Conventional cell lattice parameters

a 4.427 Å , b 4.434 Å , c 6.723 Å

α 90.114 ° , β 89.946 ° , γ 119.895 °

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Structural analysis

The following shows the X-ray diffraction (XRD) pattern and the Radial distribution function (RDF) plots. XRD peaks should be comparable to experiments for bulk structures. Relative intensities may differ.

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): 0.1171I

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 : 0.0468 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 : 0.0064 eV

Magnetic moment

The orbital magnetic moment was obtained after SCF run. Please note no DFT+U parameters were taken into account.

na μB

Reference

mp-995181