Elastic constants of α-GeO2

Abstract

The elastic constants of α-GeO2, the quartzlike polymorph of germanium dioxide, have been determined using Brillouin scattering. The data were obtained using a high quality single crystal of α-GeO2. When compared with existing data on α-SiO2, our results show that the shear constants are considerably softened in GeO2. This could be an indication that the observed pressure induced phase change is related to a shear instability.