Study of electronic and optical properties of Bi0.5Na0.5TiO3, BiTiO3, NaTiO3 crystals using full potential linear argumented plane wave method

We studied the optical and electronic properties of Bi0.5Na0.5TiO3, BiTiO3, NaTiO3 compounds such as density of state function, refraction index, optical conductivity and energy gap. Calculations were performed in the framework of density functional theory (DFT), using the full-potential linearized augmented plane wave (FP-LAPW) method with generalized gradient approximation (GGA) for correlation potential, optical properties were obtained using Kramer–Kronig transformations in the imaginary dielectric tensor. The result shows that there is a remarkable difference between NaTiO3 and BiTiO3 compounds by Bi0.5Na0.5TiO3 compound for the mentioned quantities Bi0.5Na0.5TiO3, NaTiO3, BiTiO3 compounds are a direct band gap insulator with energy gap of about 1.97 eV, 2.2 eV, 2.6 eV, respectively.