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Title: Signature of a polyamorphic transition in the THz spectrum of vitreous GeO2

The THz spectrum of density fluctuations, S(Q, ω), of vitreous GeO2 at ambient temperature was measured by inelastic x-ray scattering from ambient pressure up to pressures well beyond that of the known α-quartz to rutile polyamorphic (PA) transition. We observe significant differences in the spectral shape measured below and above the PA transition, in particular, in the 30–80 meV range. Guided by first-principle lattice dynamics calculations, we interpret the changes in the phonon dispersion as the evolution from a quartz-like to a rutile-like coordination. Notably, such a crossover is accompanied by a cusp-like behavior in the pressure dependence of the elastic response of the system. Altogether, the presented results highlight the complex fingerprint of PA phenomena on the high-frequency phonon dispersion.
Authors:
 [1] ;  [2] ;  [1] ;  [3] ;  [4] ;  [5] ;  [6] ;  [7] ;  [8] ;  [9] ;  [10] ;  [1] ;  [1]
  1. Brookhaven National Lab. (BNL), Upton, NY (United States)
  2. American Physical Society, Ridge, NY (United States)
  3. Stanford Univ., Stanford, CA (United States)
  4. Institut de Mineralogie, de Physique des Materiaux et de Cosmochimie, Sorbonne Univ. - UPMC, Museum National d'Historie Naturelle, Paris (France)
  5. Sincrotrone Trieste, Trieste (Italy)
  6. Sincrotrone Trieste, Trieste (Italy); Univ. degli Studi di Trieste, Trieste (Italy)
  7. European Synchrotron Radiation Facility, Grenoble (France)
  8. Japan Synchrotron Radiation Research Institute, Hyogo (Japan)
  9. Japan Synchrotron Radiation Research Institute, Hyogo (Japan); SPring-8/RIKEN, Hyogo (Japan)
  10. Geophysical Lab. Carnegie Institution of Washington, D.C. (United States); Center for High Pressure Science & Technology Advanced Research, Shanghai (China)
Publication Date:
OSTI Identifier:
1258790
Grant/Contract Number:
SC0012704; 2010-JCJC-604-1
Type:
Accepted Manuscript
Journal Name:
Scientific Reports
Additional Journal Information:
Journal Volume: 5; Journal ID: ISSN 2045-2322
Publisher:
Nature Publishing Group
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY