On the High-Pressure Phase Transition in GaPO4

TL;DR

This study investigates the high-pressure phase transition of GaPO4 using X-ray diffraction, identifying a transition at 13.5 GPa and a subsequent orthorhombic phase stabilized by laser heating at 17 GPa.

Contribution

It provides detailed structural data on GaPO4's high-pressure phases and the conditions for phase stabilization, expanding understanding of its high-pressure behavior.

Findings

Transition to disordered crystalline form at 13.5 GPa

Orthorhombic phase with Cmcm space group at 17 GPa

Cell parameters at transition point

Abstract

X-ray diffraction (XRD) experiments have been carried out on quartz-like GaPO4 at high pressure and room temperature. A transition to a high pressure disordered crystalline form occurs at 13.5 GPa. Slight heating using a YAG infrared laser was applied at 17 GPa in order to crystallize the phase in its stability field. The structure of this phase is orthorhombic with space group Cmcm. The cell parameters at the pressure of transition are a=7.306 A, b=5.887 A and c=5.124 A.