High pressure nanoarchitectonics and metallization of barium chloride and barium bromide

Abstract

As one of the most prototypicalAX₂-type compounds, barium halide shared the cubic structure withFm-3msymmetry for BaCl₂or orthorhombic structure withPnmasymmetry for BaBr₂at ambient pressure. In this work, we explored the crystal structures of BaCl₂and BaBr₂under high pressure. We predicted a thermodynamically more favored structure with orthorhombicCmcmsymmetry for both BaCl₂and BaBr₂, at 74 and 47 GPa, respectively. Our simulations reveal that the metallic feature ofCmcmBaCl₂andCmcmBaBr₂under high pressure. The present results improve the understanding of high-pressure structures ofAX₂compounds at extremely high-pressure conditions.

Keywords: crystal structure; high pressure; phase transition.