In situ high-pressure X-ray diffraction study of densification of a molecular chalcogenide glass

• Published in: The Journal of physics and chemistry of solids Vol. 69; no. 9; pp. 2336 - 2340
• Main Authors: Soyer Uzun, S., Gaudio, S.J., Sen, S., Mei, Q., Benmore, C.J., Tulk, C.A., Xu, J., Aitken, B.G.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Oxford Elsevier Ltd 01-09-2008; Elsevier
• Subjects: A. Glasses; A. Non-crystalline materials; C. High pressure; C. X-ray diffraction; Condensed matter: structure, mechanical and thermal properties; D. Phase transitions; Disordered solids; Exact sciences and technology; Glasses; Physics; Structure of solids and liquids; crystallography; D. Phase transitions; C. High pressure; A. Non-crystalline materials; A. Glasses; C. X-ray diffraction; Densification; Pressure effects; Structure factors; Phase transformations; Glass structure; XRD; High temperature; Chalcogenide glasses; High pressure; Sulfides; Ordering
• ISSN: 0022-3697; 1879-2553
• DOI: 10.1016/j.jpcs.2008.04.004

Structural mechanisms of densification of a molecular chalcogenide glass of composition Ge
2.5As
51.25S
46.25 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 As
4S
3 molecules. At higher pressures the As
4S
3 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.