Pressure Dependence of Structural Behavior and Electronic Properties in Double Perovskite Ba₂SmSbO₆

Understanding the structural behavior of double perovskites plays a pivotal role in optimizing their optical, electrical, and magnetic properties, especially when the effects of external parameters are considered. In this work, we report the high-pressure phase transition, the light absorption, and the bandgap of double perovskite Ba2SmSbO6 investigated by using in situ high-pressure synchrotron X-ray diffraction and Raman and ultraviolet-visible (UV-vis) absorption spectroscopy measurements up to 40 GPa. We found that pressure induces the phase transition from a cubic Fm-3m to a tetragonal I4/m at 8.6-12.8 GPa, as accompanied by the splitting and broadening of the diffraction peaks. The evolution of various modes in the Raman spectra and the enthalpy calculations support the phase transition of Ba2SmSbO6 under compression. The analysis of UV-vis absorption spectroscopy reveals that the bandgap as a pressure of function is closely related to the phase transition. Calculation results demonstrate that the pressure-induced variation of the electronic structure mainly stems from the contribution of conduction states in Ba2SmSbO6. Our investigations provide a fundamental understanding of the structure-property modulation in Ba2SmSbO6 under high pressure and will functionalize a new application-pressure sensor.