Unveiling the energy driven potential Sc-based double perovskite through comprehensive DFT screening on physical, optoelectronic and transport characteristic of Sr2ScAsO6 compound

Abstract

Recently, double perovskites have been emerged as promising candidates due to their enthralling electronic as well as thermoelectric properties. In our present investigation, we have made a systematic effort to evaluate the optical properties along with elastic, mechanical and thermoelectric properties of Sr₂ScAsO₆ using DFT tactics as implemented with WIEN2k code. The exchange - correlation potential has been treated with various approximations like LDA, PBE-GGA, WC-GGA and PBE-sol GGA. The formation energy, cohesive energy and tolerance factor have been computed for the studied double perovskite to confirm its thermodynamic as well as structural stability in the cubic phase. The ductility as well as brittleness of the compound have been checked by evaluating the $B/G_H$ and Poisson's ratios. The value of band gap is found to be 2.147 eV with PBE-GGA + TB-mBJ method, which is the accurate mode of band gap computations. The spin-orbit coupling effect and its exclusion were considered during the calculations. The temperature and pressure dependency of thermodynamic properties have been studied with the aid of modified-Gibbs2 model. The thermoelectric behaviour of the studied double perovskite has been explored and found to hold a power factor of 12.2 × 10¹² W m⁻¹ K⁻² s⁻¹ at 1200 K. As these compositions have high room temperature figure of merit values and recorded values of 0.035, they are also suitable for application in thermoelectric devices.