Investigation of pressure-driven band gap variation and the physical characteristics of Ba₃SbX₃ (X = F, Cl) perovskite for potential optoelectronic applications

This work examines the influence of pressure on the structural, electrical, elastic, and optical characteristics of the new cubic Ba₃SbX₃ (X = F, Cl). This research primarily aims to diminish the electrical band gap of Ba₃SbF₃ and Ba₃SbCl₃ under pressure to enhance their optical properties and assess their suitability for optoelectronic applications. The results demonstrate that both the lattice parameter and unit cell volume diminish significantly with the application of pressure. At ambient pressure, the band structure study indicates that both Ba₃SbF₃ and Ba₃SbCl₃ possess direct band gaps. As pressure ascends from 0 GPa to 15 GPa, the electronic band gap for Ba₃SbF₃ (Ba₃SbCl₃) diminishes from 0.943 (0.908) eV to 0.039 (0.047) eV, indicating a substantial decrease. The application of hydrostatic pressure yields ideal band gap values for both Ba₃SbF₃ and Ba₃SbCl₃, offering robust theoretical evidence for the modulation of the band gaps of both perovskites. The elastic properties, determined by the Thermo-PW tool, indicate that these materials are anisotropic, mechanically stable, ductile, and resistant to plastic deformation. Moreover, their mechanical qualities enhance considerably under pressure. The optoelectronic properties were computed for the 0-30 eV energy range under various pressure settings. The optical characteristics underscore the versatility of Ba₃SbF₃ and Ba₃SbCl₃ perovskites, rendering them viable candidates for pressure-tunable optoelectronic devices.