First principles calculation on elastic, electronic and optical properties of new cubic (Pm3m) pb-free perovskite oxide of SnZrO3

The geometry optimization, elastic constant, electronic band structure, density of state (DOS) and optical properties of perovskite SnZrO₃ (SZ) are investigated from first principles calculation using the Density Functional Theory (DFT) within Local Density Approximation (LDA). All the calculations are performed using the Cambridge Serial Total Energy Package (CASTEP) computer code. The independent elastic constants (C₁₁, C₁₂, and C₄₄), bulk modulus, B are obtained and analyzed. From the calculation along the higher symmetry direction in the Brillouin zone, direct band gap of SZ is 3.09 eV at X point and DOS shows the strong hybridization between cation Pb 5p and O 2p compare to hybridization of cation Zr 4d and O 2p. To understand the optical properties of SnZrO₃, the complex dielectric constant for radiation up to 30 eV was investigated. Results show that anion O 2p, cation Sn 5p and Zr 4d states play an important role in optical transition and it is respectively correspond to the top of valence states and bottom of conduction band. The results were compared and showed in good agreement with other calculated SnTiO₃.