Molecular dynamics study of pressure-induced transformation of quartz-type GeO₂

Abstract

We simulated quartz-type GeO₂ and investigated its high-pressure transformation using the molecular dynamics (MD) simulation method with a model potential. The calculated results under hydrostatic compression indicated that a pressure-induced amorphization of quartz-type GeO₂ originated from the mechanical instability of the quartz lattice as, in previous theoretical studies of SiO₂. Furthermore, quartz-type GeO₂ directly transformed to a rutile-like structure with only subtle displacements of ions under σ _{x y} imposed shear stressed decompression. This is the first reproduction of the quartz-to-rutile transformation. A possible pathway of this transition is proposed in this study.