Structural and Electronic Transitions in AgReO4 Under Pressure

Abstract

AbstractThe behavior of AgReO4 under pressure has been studied in a diamond anvil cell. The equation of state determined by synchrotron radiation shows considerable change in compressibility with increasing pressure. X-ray and Raman scattering show a first-order phase transition from the scheelite to an as yet undetermined structure at 13 GPa. Changes in both the internal and external Raman active modes suggest a change in Re coordination. Optical transmission experiments demonstrate that the energy gap in the scheelitephase decreases at the rate of 75 meV/GPa. There is a small jump in the energy gap at 13 GPa, probably related to the structural transition. AgReO4 remains aninsulator to at least 47 GPa.