Pressure-driven modulation of the photocatalytic properties of BaGaO₃: A first-principles investigation

In this research, cubic perovskite BaGaO₃ was studied for its structural, electronic, optical, and mechanical properties using a first-principles density functional theory (DFT) approach under varying hydrostatic pressure from 0 to 50 GPa. The Hey-Scuseria-Ernzerhof (HSE03) exchange-correlation functional was employed for electronic properties and GGA-PBE was employed for other physical properties. The cubic structure was maintained, with a steady decrease in unit cell volume and lattice constants as pressure increased, confirming the typical compressibility of perovskites. The analysis of the electronic band structure indicated an indirect band gap, which widens from 2.03 eV at ambient conditions to 4.96 eV at 50 GPa, suggesting enhanced insulating properties. The partial density of states (PDOS) reveals a pressure-induced shift in orbital contributions, indicating longer carrier lifetimes and reduced electron-hole recombination potential. Optical properties, including refractive index, dielectric constant, absorption, and reflectivity, peaked around 25-30 GPa, signifying strong light-matter interactions and potential for optoelectronic applications. Mechanical property analysis, such as elastic constants and related parameters, confirmed increased hardness, stiffness, and ductility with rising pressure, while satisfying all stability criteria outlined by Born. The potential for water splitting was estimated by estimating Hydrogen Evolution Reaction (0eV vs NHE) and Oxygen Evolution Reaction OER (1.23eV vs NHE). This revealed that VBE (Valence Band Edge) is more positive than that of CBE (Conduction Band Edge). This specifies the suitability of BaGaO₃ for photocatalysis under variable stress. These findings identify BaGaO₃ as a pressure-tolerant, promising, and robust material suitable for photocatalysis, advanced optoelectronic devices and high-pressure environments. This research expands the database of pressure-tunable cubic perovskite materials.