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Title: Ultrahigh-pressure polyamorphism in GeO 2 glass with coordination number >6

Knowledge of pressure-induced structural changes in glasses is important in various scientific fields as well as in engineering and industry. However, polyamorphism in glasses under high pressure remains poorly understood because of experimental challenges. We report new experimental findings of ultrahigh-pressure polyamorphism in GeO 2 glass, investigated using a newly developed double-stage large-volume cell. The Ge–O coordination number (CN) is found to remain constant at ~6 between 22.6 and 37.9 GPa. At higher pressures, CN begins to increase rapidly and reaches 7.4 at 91.7 GPa. This transformation begins when the oxygen-packing fraction in GeO 2 glass is close to the maximal dense-packing state (the Kepler conjecture = ~0.74), which provides new insights into structural changes in network-forming glasses and liquids with CN higher than 6 at ultrahigh-pressure conditions.
Authors:
 [1] ;  [1] ;  [1] ;  [2] ;  [3] ;  [1]
  1. Carnegie Inst. of Washington, Argonne, IL (United States). Geophysical Lab., High Pressure Collaborative Access Team (HPCAT)
  2. Tohoku Univ., Sendai (Japan). Frontier Research Inst. for Interdisciplinary Sciences
  3. Univ. of Chicago, IL (United States). Center for Advanced Radiation Sources (CARS)
Publication Date:
Grant/Contract Number:
FG02-99ER45775; NA0001974; AC02-06CH11357; EAR-1128799; FG02-94ER14466; EAR-1214376
Type:
Published Article
Journal Name:
Proceedings of the National Academy of Sciences of the United States of America
Additional Journal Information:
Journal Volume: 113; Journal Issue: 13; Journal ID: ISSN 0027-8424
Publisher:
National Academy of Sciences, Washington, DC (United States)
Research Org:
Carnegie Inst. of Washington, Argonne, IL (United States); Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Chemical Sciences, Geosciences & Biosciences Division; USDOE National Nuclear Security Administration (NNSA); National Science Foundation (NSF)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; high pressure; polyamorphism; glass; oxygen packing
OSTI Identifier:
1241555
Alternate Identifier(s):
OSTI ID: 1469294