Formation and structure of a dense octahedral glass.
PHYSICAL REVIEW LETTERS 2004;
93:115502. [PMID:
15447351 DOI:
10.1103/physrevlett.93.115502]
[Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2004] [Indexed: 05/24/2023]
Abstract
We have performed in situ x-ray and neutron-diffraction measurements, and molecular dynamics simulations, of GeO2, an archetypal network-forming glass under pressure. Below 5 GPa, additional atoms encroaching on the first tetrahedral shell are seen to be a precursor of local coordination change. Between 6 and 10 GPa, we observe structures with a constant average coordination of approximately 5, indicating a new metastable, intermediate form of the glass. At 15 GPa, the structure of a fully octahedral glass has been measured. This structure is not retained upon decompression and, therefore, must be studied in situ.
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