Multifunctionality in Lead-Free Rb2XTaBr6 (X = Na, Li) Double Perovskites: A First-Principles Study of Structural, Elastic, Optoelectronic, and Thermoelectric Properties
First-principles FP-LAPW calculations were used to investigate the structural, mechanical, electronic, optical, and thermoelectric properties of the double halide perovskites Rb2NaTaBr6 and Rb2LiTaBr6. Structural optimization confirmed their stable cubic phase. Elastic analysis shows they are mechanically stable, ducti...