Pressure-induced modifications in the structural and optoelectronic behavior of Ba ₂ LuNbO ₆ : a first-principles study for photovoltaic applications

The physical characteristics of double perovskite oxides have made them a desirable option due to their effective bandgap tunability. This bandgap tunability is affected by cation engineering, doping, and pressure modulation. These strategies enable precise control over the electronic structure, making double perovskite oxides promising candidates for photovoltaic applications. In this manuscript, we have analyzed the physical traits of cubic Ba 2 LuNbO 6 with pressure modulation. The pressure values are selected as 0 GPa, 10 GPa, 20 GPa, and 30 GPa. The quantum mechanical interactions between ions and electrons in the material are addressed via the mBJ approximation. Ba 2 LuNbO 6 is structurally and thermodynamically stable according to the parameters obtained from Birch’s equation. Cubic formation is guaranteed from the obtained results of the tolerance factor and octahedral tilting. Hooke’s law is used to express the linear relation between stress and strain. The computed elastic traits report a decreasing trend with an increase in pressure. As pressure is raised, a noticeable decrease in the material's stiffness and rigidity is seen. With pressure increment, the atomic bonding becomes weaker and the lattice becomes softer. Higher pressure causes a brittle-to-ductile transition for Ba 2 LuNbO 6 . Elastic waves, Debye, and melting temperatures imply that as pressure is increased, the thermal stability of the studied material declines. The electronic properties of the studied oxide report a declining trend from 3.70 eV (0 GPa) to 1.25 eV (30 GPa). With an increase in pressure, the optical analysis shows a notable shift in the peaks from the high-energy region to the low-energy region for conductivity, absorption, and reflectivity, indicating that Ba 2 LuNbO 6 has the potential to be used in pressure-related photovoltaic devices.