DFT study of physical properties of the halide perovskites XAlBr 3 (X = Ca, Sr, Ba)

This study focuses on the halide perovskites XAlBr3 (X = Ca, Sr, Ba), examining their structural, mechanical, electronic, thermodynamic, and optical properties. All three compounds exhibit a stable cubic crystal structure with non-magnetic ground states. Mechanically, the compounds exhibit isotropic elasticity and moderate resistance to volumetric deformation of soft halide perovskites (bulk moduli: 12.7–20.5 GPa). From calculations based on electronic structure, these materials function as indirect bandgap semiconductors with band gaps between 3.21 and 3.57 eV. Some thermodynamic parameters, such as specific heat capacity, entropy, or Debye temperature, exhibited gradual trends commensurate with variable temperatures, which suggests solid thermal stability and low hysteresis behavior within an extensive temperature range. Furthermore, through optical means, the materials displayed distinct refractive and extinction profiles, showcasing considerable ultraviolet region absorption. These characteristics signify the value of XAlBr3 for development in energy-related and optoelectronic applications.