TY  - JOUR
A1  - Petitgirard, Sylvain
A1  - Spiekermann, Georg
A1  - Glazyrin, Konstantin
A1  - Garrevoet, Jan
A1  - Murakami, Motohiko
T1  - Density of amorphous GeO2 to 133 GPa with possible pyritelike structure and stiffness at high pressure
JF  - Physical review : B, Condensed matter and materials physics
N2  - Germanium oxide is a prototype network-forming oxide with pressure-induced structural changes similar to those found in crystals and amorphous silicate oxides at high pressure. Studying density and coordination changes in amorphous GeO2 allows for insight into structural changes in silicate oxides at very high pressure, with implications for the properties of planetary magmas. Here, we report the density of germanium oxide glass up to 133 GPa using the x-ray absorption technique, with very good agreement with previous experimental data at pressure below 40 GPa and recent calculation up to 140 GPa. Our data highlight four distinct compressibility domains, corresponding to changes of the local structure of GeO2. Above 80 GPa, our density data show a compressibility and bulk modulus similar to the counterpart crystal phase, and we propose that a compact distorted sixfold coordination, similar to the structural motif of the pyritelike crystalline GeO2 polymorph, is likely to be stable in that pressure range. Our density data point to a smooth continuous evolution of the average coordination for pressure above 20 GPa with persistent sixfold coordination, without sharp density or density slope discontinuities. These observations are in very good agreement with theoretical calculations and spectroscopic measurements, and our results indicate that glasses and melts may behave similarly to their high-pressure solid counterparts with comparable densities, compressibility, and possibly average coordination.
Y1  - 2019
U6  - https://doi.org/10.1103/PhysRevB.100.214104
SN  - 2469-9950
SN  - 2469-9969
VL  - 100
IS  - 21
PB  - American Physical Society
CY  - College Park
ER  -