First principles investigation of structural, electronic, optical, transport properties of double perovskites X2TaTbO6 (X= Ca, Sr, Ba) for optoelectronic and energy harvesting applications

Structural, electrical, optical, thermoelectric response of X₂TaTbO₆ (X = Ca, Sr, Ba) double perovskites oxides are studied by using WIEN2k that is based on quantum mechanical calculations employing PBE-GGA approximation under the framework of DFT. We present electronic attributes including band gaps and density of states, and explain the electronic properties of all three oxide double perovskite materials which proved that they belong to directly forbidden band gap materials family. The cubic compounds Ba₂TaTbO₆, Sr₂TaTbO₆, and Ca₂TaTbO₆ have respective direct band gaps of 2.35 eV, 2.15eV, and 2.25 eV. Optical conductivity σ(ω), reflection R(ω), complex dielectric constants, refractive index ƞ(ω), absorbance α(ω), loss parameter L(ω) and extinction coefficient K(ω) are all utilized to explore light dependent characteristics of studied compounds. Thermoelectric parameter like, Number of Seebeck effect (S), charge carrier (n), magnetic susceptibility, power factor (PF), electrical conductivity (σ/t), thermal conductivity K/t, and heat capacity are key characteristics for materials to study its ability of thermal behavior. These thermoelectric parameters were determined by using BoltzTraP code. By studying the numbers on various material properties, scientists are uncovering new possibilities for creating sustainable materials for sustainable gadgets.