Structural phase transition and physical properties in NaBr under high pressure

Abstract

The simple cubic structure and highly ionic bonding characteristics of Alkali halide NaBr have garnered significant attention in the field of fundamental physics. Previous X-ray diffraction studies revealed a phase transition from B1 to B33 phase in NaBr under pressure. However, the experimental determination of the phase transition pressure suffered from large errors due to the absence of a pressure transfer medium and high-water absorption in NaBr samples. To overcome these limitations, we employ DFT calculations to investigate the phase transition behavior of NaBr up to 40 GPa. Our theoretical analysis reveals a “first-order” phase transition at 25 GPa and provides comprehensive insights into the pressure-dependent physical properties.