High-pressure behaviour of GeO2: a simulation study

TL;DR

This study uses molecular dynamics simulations to explore the high-pressure behavior of liquid and glassy GeO2, revealing structural transitions and anomalous diffusivity similar to silica and water.

Contribution

It introduces a first-principles parameterized potential for GeO2 and provides detailed insights into its pressure-induced structural and dynamic changes.

Findings

Smooth transition from tetrahedral to octahedral GeOn networks with pressure

Confirmation of anomalous diffusivity behavior in high-pressure liquid GeO2

Identification of penta-coordinated germanium ions as key to anomalous behavior

Abstract

In this work we study the high pressure behaviour of liquid and glassy GeO2 by means of molecular dynamics simulations. The interaction potential, which includes dipole polarization effects, was parameterized from first-principles calculations. Our simulations reproduce the most recent experimental data to a high degree of precision. The proportion of the various GeOn polyhedra is determined as a function of the pressure: a smooth transition from tetrahedral to octahedral network is observed. Finally, the study of high-pressure, liquid germania confirms that this material presents an anomalous behaviour of the diffusivity as observed in analog systems such as silica and water. The importance of penta-coordinated germanium ions for such behaviour is stressed.