Investigation of lead-free direct bandgap Ca 2 MAsO 6 (M=Ga, In) double perovskites for optoelectronic and thermoelectric applications: A first principles study

In this study, an extensive investigation into the multiple characteristics of Ca 2 MAsO 6 (M=Ga, In), double perovskite materials, focusing on their structural, mechanical, electronic, optical, and thermoelectric properties utilizing the density functional theory is explored. The structural and mechanical stability of these materials with a cubic structure is confirmed by the tolerance factors, octahedral factors, and mechanical stability assessments. Moreover, these materials exhibit an isotropic nature with high rigidity. The calculated band structures reveal that these materials exhibit a band gap of 2.61 eV for Ca 2 GaAsO 6 and 2.83 eV for Ca 2 InAsO 6 with direct band gap in nature. Additionally, the optical properties reveal that effective absorption takes place within the ultraviolet region in the electromagnetic spectrum. The band structure and optical properties make these materials suitable for optoelectronic applications. Finally, the calculated thermoelectric properties, namely Seebeck coefficient, electrical and thermal conductivity, and figure of merit indicate that these materials possess advantageous thermoelectric traits, further solidifying their potential candidacy for thermoelectric devices.