Theoretical analysis of the structural, electronic and optical properties of tetragonal Sr2GaSbO6

Structural, electronic and optical properties of the tetragonal structure Sr2GaSbO6 compound have been investigated using a full relativistic version of the full-potential augmented plane-wave method. The generalized gradient approximation (GGA) is used as an exchange correlation potential with Perdew-Burk-Ernzerhof (PBE) and Engel-Vosko (EV) as exchange correlation functional. The lattice parameters (a, c) are optimized and found in good agreements with the available experimental data. Results are given for bulk modulus B and the pressure derivative of the bulk modulus B'. Band structure and densities of states (DOS) of tetragonal Sr2GaSbO6 have been obtained. The EV-GGA scheme was selected to obtain better band gap value (1.00 eV) as compared to GGA-PBE (0.75 eV). Furthermore, in order to clarify the mechanism of optical transitions of tetragonal Sr2GaSbO6, the complex dielectric function, refractive index and extinction coefficient were calculated for radiation up to 20 eV.