Tunable physical properties of A-site double perovskite KLaYBiO ₆ under hydrostatic pressure: Implications for renewable energy technologies

A-site perovskite oxides are notable because of their remarkable structural flexibility, which allows them to display a wide range of physical features such as strong ionic conductivity, magnetism and ferroelectricity. They are widely employed in several applications, including fuel cells, sensors and catalysis. Applied pressure can alter their crystal structure, electrical arrangement and phase transitions, boosting or inhibiting their physical attributes. In this work, we have studied the pressure effect on the physical properties of the A-site double perovskite oxide KLaYBiO 6 using first principles analysis. The FP-LAPW methodology is employed along with the mBJ approximation to accurately calculate the pressure effect on KLaYBiO 6 . The pressure is applied till 12[Formula: see text]GPa in step sizes of 4[Formula: see text]GPa. The volume optimization curves and formation energies evaluated at each pressure confirm structural stability. The obtained elastic constants show a dropping trend as pressure is increased and also justify Born’s stability criteria at each pressure. KLaYBiO 6 stays ductile as pressure is increased to 12[Formula: see text]GPa. The electronic properties report a significant reduction in the bandgap from 2.18 to 1.54[Formula: see text]eV. The optical properties report the shifting of peaks from the UV to the visible region as the pressure is enhanced. These findings report that applying pressure to the A-site double perovskite oxide KLaYBiO 6 results in tunable physical attributes, leading to notable changes in its properties. This provides a pathway for engineering the material’s characteristics for targeted applications such as fuel cells, sensors, or electronic devices.