Electronic properties of orthorhombic InI and TlI crystals taking into account the quasiparticle corrections and spin-orbit interaction

The electronic properties of InI and TlI crystals of an orthorhombic structure with a space group Cmcm are studied. Calculations of electron properties are performed on the basis of the projector augmented waves by means of the ABINIT program. Total and partial densities of electronic states are calculated. Electron energy spectra are found with the exchange-correlation functional GGA, without and taking into account the spin-orbital interaction. It was found that the bandgap of the InI, obtained without spin-orbital interaction, is less than the experimental value by 38%, and by 42%, taking into account the latter. For the TlI crystal, the corresponding values are 27% and 39%. The bandgap found from the quasiparticle equation in the GW approximation exhibits an excellent agreement with the experimental values for both crystals.