Phase Transitions and Electric Properties of PbBr 2 under High Pressure: A First-Principles Study.

PbBr2 has recently attracted considerable attention as a precursor for lead halide perovskite-based devices because of its attractive properties. It is known that pressure can modify the chemical and physical properties of materials by altering the distance between atoms in the lattice. Here, a global structure-searching scheme was used to explore the high-pressure structures of PbBr2, whose structures and properties at high pressure are still far from clear. Three new phases of PbBr2 were predicted in the pressure range of 0–200 GPa, and the pressure-driven phase transition sequence of orthorhombic Pnma (0–52 GPa) → tetragonal I4/mmm (52–80 GPa) → orthorhombic Cmca (80–153.5 GPa) → orthorhombic Immm (153.5–200 GPa) is proposed. Electronic calculations indicate a semiconductor-to-metallic transition of PbBr2 in the Cmca phase at ~120 GPa. Our present results could be helpful in improving the understanding of fundamental physical properties and provide insights to modulate the structural and related photoelectric properties of PbBr2. [ABSTRACT FROM AUTHOR]