First principles study of the electronic and optical properties of SbTaO 4

Abstract

The electronic density of states (DOS), band structure and optical properties of orthorhombic SbTaO 4 are studied by first principles full potential-linearized augmented plane wave (FP-LAPW) method. The calculation is done in the framework of density functional theory with the exchange and correlation effects treated using generalized gradient approximation (GGA). We find an indirect band gap of 1.9 eV at the R→Γ symmetry direction of the Brillouin zone in SbTaO 4. It is observed that there is a strong hybridization between Ta-5d and O-2p electronic states which is responsible for the electronic properties of the system. Using the projected DOS and band structure we have analyzed the interband contribution to the optical properties of SbTaO 4. The real and imaginary parts of the dielectric function of SbTaO 4 are calculated, which correspond to electronic transitions from the valence band to the conduction band. The band gap obtained is in close agreement with the experimental data.