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Network rigidity in GeSe2 glass at high pressure
Sytle M Antao1, Chris J Benmore, Baosheng Li
1Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA. sytle.antao@anl.gov
Physical Review Letters
|June 4, 2008
Summary
Researchers studied the structural transition of glassy germanium diselenide (GeSe2) under high pressure. Acoustic measurements revealed a network rigidity minimum due to competing densification mechanisms, impacting the material
Area of Science:
- Materials Science
- Condensed Matter Physics
- Geophysics
Background:
- Glassy materials exhibit unique properties under high pressure.
- Understanding structural transitions is key to predicting material behavior.
Purpose of the Study:
- To investigate the high-pressure acoustic properties of glassy GeSe2.
- To elucidate the structural mechanisms governing its behavior up to 9.6 GPa.
Main Methods:
- Acoustic measurements utilizing synchrotron radiation.
- Analysis of shear-wave velocity, Poisson's ratio, and elastic moduli.
Main Results:
- Observed a minimum in shear-wave velocity and anomalous Poisson's ratio.
- Identified discontinuities in elastic moduli around 4 GPa, indicating a structural transition.
- Linked the transition to a network rigidity minimum driven by competing densification processes.
Conclusions:
- Glassy GeSe2 undergoes a gradual structural transition under pressure.
- Densification involves a shift from edge- to corner-sharing tetrahedra (up to 3 GPa), increasing flexibility.
- Increased coordination number at higher pressures leads to network stiffening.
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