Pressure-induced tuning of physical properties in high-throughput metal halide MSn 2 Br 5 (M = K, Cs) perovskites for optoelectronic applications.

The physical properties of the ferromagnetic oxide perovskites MSn 2 Br 5 (M = K, Cs) were thoroughly examined using the GGA + PBE formalism of density functional theory. The investigation includes a comprehensive characterization of these materials under hydrostatic pressures ranging up to 25 GPa. Our work represents the first theoretical framework for exploring the behavior of MSn 2 Br 5 (M = K, Cs) under pressure, providing valuable insights into their properties. To ensure the thermodynamic and mechanical stability of the studied compounds, we justified their stability through the analysis of formation energy and Born stability criteria. Furthermore, we conducted a thorough examination of the mechanical features of MSn 2 Br 5 (M = K, Cs) based on various parameters, such as elastic constants, elastic moduli, the Kleinman parameter, the machinability index, and the Vickers hardness. Pugh's ratio and Poisson's ratio data show a ductile behavior for both compounds under stress. Moreover, our analysis of the refractive index suggests that both materials hold significant potential as candidates for ultrahigh-density optical data storage devices, particularly when subjected to appropriate laser irradiation. This finding opens up exciting possibilities for utilizing MSn 2 Br 5 (M = K, Cs) in advanced optical technologies.