Multifunctional properties of the double perovskite Ca₂GaAsO₆ investigated using density functional theory

Abstract A first-principles study of the structural, electronic, magnetic, mechanical, and optical properties of the double perovskite Ca₂GaAsO₆ is presented using density functional theory with the Perdew-Burke-Ernzerhof generalized gradient approximation (PBE-GGA). Additionally, the Tran–Blaha modified Becke–Johnson (TB-mBJ) potential is employed to more accurate analysis of the electronic and optical properties. By evaluating the tolerance factor, determining the negative formation energy, and meeting the Born mechanical stability requirements, the thermodynamic and mechanical stability of the cubic phase is verified. High stiffness and isotropic (A = 1.21) mechanical behaviour are revealed by elastic constant analysis, suggesting strong mechanical robustness. Ca₂GaAsO6 is a direct band gap semiconductor with a band gap of 2.61 eV for TB-mBJ and 0.87 eV for PBE-GGA, according to electronic band-structure calculations. Strong ultraviolet absorption is observed in the optical property analysis, consistent with the large band gap. These findings demonstrate the potential of Ca₂GaAsO6 for ultraviolet optoelectronic applications, photodetectors, and UV light-emitting diodes. To fully utilise its technological potential, more synthesis and device-integration experiments are needed.