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In situ high-pressure X-ray diffraction study of densification of a molecular chalcogenide glass |
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| Authors: | S. Soyer Uzun S. Sen C.J. Benmore C.A. Tulk B.G. Aitken |
| Affiliation: | a Department of Chemical Engineering and Materials Science, University of California, Davis, CA 95616, USA b X-ray Science and Intense Pulsed Neutron Source Divisions, Argonne National Laboratory, Argonne, IL 60439, USA c Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA d Carnegie Institution of Washington, 5251 Broadbranch Road, N.W., Washington, DC 20015, USA e Glass Research Division, Corning Inc, Corning, NY 14831, USA |
| Abstract: | Structural mechanisms of densification of a molecular chalcogenide glass of composition Ge2.5As51.25S46.25 have been studied in situ at pressures ranging from 1 atm to 11 GPa at ambient temperature as well as ex situ on a sample quenched from 12 GPa and ambient temperature using high-energy X-ray diffraction. The X-ray structure factors display a reduction in height of the first sharp diffraction peak and a growth of the principal diffraction peak with a concomitant shift to higher Q-values with increasing pressure. At low pressures of at least up to 5 GPa the densification of the structure primarily involves an increase in the packing of the As4S3 molecules. At higher pressures the As4S3 molecules break up and reconnect to form a high-density network with increased extended-range ordering at the highest pressure of 11 GPa indicating a structural transition. This high-density network structure relaxes only slightly on decompression indicating that the pressure-induced structural changes are quenchable. |
| Keywords: | A. Glasses A. Non-crystalline materials C. High pressure C. X-ray diffraction D. Phase transitions |
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