Investigation on the electronic structure, optical, elastic, mechanical, thermodynamic and thermoelectric properties of wide band gap semiconductor double perovskite Ba₂InTaO₆

Abstract

In the present paper, double perovskite Ba₂InTaO₆ was investigated in terms of its structural, electronic, optical, elastic, mechanical, thermodynamic and thermoelectric properties using density-functional theory (DFT). The generalized gradient approximation (GGA) in the scheme of Perdew, Burke and Ernzerhof (PBE) and the modified Becke-Johnson (mBJ) potential were employed for the exchange-correlation potential. The computed lattice constant was found to be in agreement with the available experimental and theoretical results. The electronic profile shows a semiconducting nature. Further analysis of the complex dielectric constant <i>ε</i>(<i>ω</i>), refractive index <i>n</i>(<i>ω</i>), reflectivity <i>R</i>(<i>ω</i>), absorption coefficient <i>α</i>(<i>ω</i>), optical conductivity (<i>ω</i>) and energy loss function were also reported with the incident photon energy. The elastic constants were also calculated and used to determine mechanical properties like Young's modulus (<i>Y</i>), the shear modulus (<i>G</i>), Poisson's ratio (<i>ν</i>) and the anisotropic factor (<i>A</i>). The electrical conductivity (<i>σ</i>/<i>τ</i>) and Seebeck coefficient (<i>S</i>) also demonstrated the semiconducting nature of the compound with electrons as the majority carriers. The value of the power factor was calculated to be 1.20 × 10¹² W K^-2 m^-1 s^-1 at 1000 K. From thermodynamic investigations, the heat capacity and Grüneisen parameter were also predicted.