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Structural formula: Cu2 Se4 Br2

Functional: optB88-vDW

Space group : P2_1

Calculation type: 1L

JARVIS ID: JVASP-13612

Formation energy/atom (eV): -0.103

Relaxed energy/atom (eV): -0.8595

Primitive cell lattice parameters

a 7.753 Å , b 4.906 Å , c 25.614 Å

α 90.0 ° , β 113.569 ° , γ 90.0 °

Conventional cell lattice parameters

a 7.753 Å , b 4.906 Å , c 23.609 Å

α 90.0 ° , β 96.05 ° , γ 90.0 °

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Convergence

Calculations are done using VASP software. Convergence on KPOINTS and ENCUT is done with respect to total energy of the system within 0.001 eV tolerance. Please note convergence on KPOINTS and ENCUT is generally done for target properties, but here we assume energy-convergence with 0.001 eV should be sufficient for other properties also. The points on the curves are obtained with single-point calculation (nuber of ionic steps,NSW=1). However, for very accurate calculations, NSW>1 might be needed.

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): 0.7553I

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 : 0.7671 eV

Magnetic moment

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

0.000 μB

Reference


mp-29567-1L
mp-29567-1L

ICSD-ID: None