Computational Prediction on the Stability, Opto-electronic and Thermoelectric Properties of Double Perovskite Compound Sr₂CrBiO₆: a First Principles Investigation

The structural, mechanical, optical, magneto-electronic, thermodynamic, and thermoelectric properties have been studied of the double perovskite (DP) Sr₂CrBiO₆ at high temperatures by using PBE, mBJ and mBJ + SOC approximations with first-principles calculations. The DP Sr₂CrBiO₆ exhibits semiconductor traits and ferromagnetic attributes under ambient conditions. Further, different physical aspects have been discussed at elevated pressure and temperature. The material shows a direct band gap of semiconducting behaviour in both channels (spin-up and spin-down). Additionally, it is susceptible to brittleness. The results were acquired by utilising electromagnetic and elastic methodologies. For the study of optical properties, different factors like reflectivity \(\:R\left(\omega\:\right)\) , index of refraction \(\:n\left(\omega\:\right)\) , complex dielectric constant \(\:\epsilon\:(\omega\:\) ), absorption coefficient \(\:\alpha\:(\omega\:\) ), and optical conductivity ( \(\:\sigma\:\left(\omega\:\right)\) ) are used for a photon energy of up to 30 eV to perceive the optical response. To figure out the lattice thermal conductivity (κ_L), different mechanical and thermal factors, such as the Debye temperature ( \(\:{\theta\:}_{D}\) ), are calculated. Measurements were taken to find out the lattice thermal conductivity (κ_L/τ), electrical conductivity (σ/τ), Seebeck coefficient (S), and Power factor (PF) at temperatures ranging from 200 K to 1200 K. The specific heat capacity ( \(\:{C}_{V}\) ) starts rising gradually from 100 K and reaches at the Dulong-Petit limit of 242 J/mol.K. The DP compound exhibits significant features of a high S and σ/τ, which are in line with its semiconducting properties depending on temperature and pressure via the quasi-harmonic Debye model. As a result, it demonstrates significant potential for utilisation in thermoelectric applications. The double perovskite compound Sr₂CrBiO₆ has exhibited significant potential for utilisation in optoelectronic devices that operate within the ultraviolet energy range.