# Dynamic compression of glassy GeO$2$ up to the TPa range and first observation of shock induced crystallization

## TL;DR

This study explores the behavior of glassy GeO$_2$ under extreme laser-induced compression, revealing its equation of state up to TPa pressures, optical property changes, and the first observation of shock-induced crystallization into rutile phase.

## Contribution

It provides the first experimental evidence of shock-induced crystallization of glassy GeO$_2$ and extends the Hugoniot equation of state to the TPa range for this material.

## Key findings

- Optical properties change from transparent to metallic under compression.
- Crystallization into rutile phase observed at pressures above 20 GPa.
- Melting occurs around 75 GPa.

## Abstract

In this work we present an extensive study of glassy GeO$_2$ under laser induced dynamic compression. New VISAR and SOP data provide the extension of Hugoniot EoS up to the TPa range for this material including temperature measurements. Reflectivity data at both 532 and 1064 nm wavelenght are also reported. In the low compression range we observe changes of the optical properties from transparent, to opaque, to metallic state. The second part of this work describes a further laser shock experiment combined with in-situ X-ray diffraction. Here we observe, for the first time, the laser shock-induced crystallization of glassy GeO$_2$ to a structure compatible with the rutile phase at pressure higher than 20 GPa and melting occurring at around 75 GPa.