TB-mBJ Calculations of Structural and Optoelectronic Properties of the Rhombohedral Phase of Bismuth Sodium Titanate (Bi<sub>0.5</sub> Na<sub>0.5</sub>)TiO<sub>3</sub>

Abstract

In the present work, we report an ab initio investigation of the structural, electronic and linear optical properties of (Na0.5Bi0.5)TiO3 (NBT) in its rhombohedral phase, using a Full Potential Augmented Plane Waves (FP-LAPW) method in the frame work of Density Functional Theory (DFT) with the TB-mBJ potential for a better description of the electronic properties. Firstly a Full structure optimization was performed with a relaxation of atomics positions to minimize the Hellmann-Feynman forces exerted over the atoms. The calculated lattice parameters of the rhombohedral phase of NBT are in very good agreement with experimental values with a deviation of 0.9%. The electronic density of states are presented and commented. The calculated band structure shows that our compound has an indirect band gap of 3.30eV. Furthermore, the optical properties were presented, compared with experimental ones present in the literature and commented.