High pressure nanoarchitectonics and metallization of barium chloride and barium bromide

Abstract

Abstract As one of the most prototypical AX 2-type compounds, barium halide shared the cubic structure with Fm−3m symmetry for BaCl2 or orthorhombic structure with Pnma symmetry for BaBr2 at ambient pressure. In this work, we explored the crystal structures of BaCl2 and BaBr2 under high pressure. We predicted a thermodynamically more favored structure with orthorhombic Cmcm symmetry for both BaCl2 and BaBr2, at 74 and 47 GPa, respectively. Our simulations reveal that the metallic feature of Cmcm BaCl2 and Cmcm BaBr2 under high pressure. The present results improve the understanding of high-pressure structures of AX 2 compounds at extremely high-pressure conditions.