First principle study of electronic and optical properties of the cubic perovskite BaSnO3

Electronic, structural and optical properties of the cubic perovskite BaSnO3 have been calculated using the full potential linearized augmented plane wave (FP-LAPW) based on density functional theory (DFT). Exchange and correlation effects are taken into account by a generalized gradient approximation (GGA) and an orbital independent modified Becke–Johanson (MBJ) potential as coupled with GGA. The structural properties including the lattice constant, the bulk modulus and the pressure derivative of the bulk modulus are calculated. The results of our calculations are in good agreement with available theoretical and experimental data. We have also calculated the energy band gap using MBJGGA. The calculated indirect band gap (R→ΓR→Γ) is 2.65 eV, while the smallest direct band gap (Γ→ΓΓ→Γ) is 3.0 eV. The real and imaginary parts of dielectric function, refractive index, real part of optical conductivity, optical absorption coefficient and the energy loss function are also calculated. Furthermore, we have analyzed the interband contribution to the optical properties of the cubic BaSnO3 using the calculated band structure and the density of states. The spin–orbit coupling has been taken into account to calculate the frequency-dependent dielectric function and it is found to be quite small.