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

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.