Electronic phase transition and amorphization in AuIn₂ at high pressure

Abstract

High-resolution angular-dispersive x-ray diffraction shows that the intermetallic compound AuIn₂ retains its initial CaF₂ structure to pressures of 23 GPa. We observe continuous broadening of diffraction lines with pressure, leading to amorphization at 24 GPa. The pressure-volume equation of state exhibits an anomaly around 2.7 GPa, in agreement with previous findings and not attributable to nonhydrostaticity. Instead, ab initio plane-wave self-consistent field calculations indicate that the observed anomaly is associated with topological changes in the electronic band structure under pressure.