Structural interpretation of the infrared and Raman spectra of glasses in the alloy system Ge1−xSx

作者：Gerald Lucovsky, Frank L. Galeener, Richard C. Keezer, R. H. Geils, H. A. Six · 发表于：Physical review. B, Solid state · 年份：1974 · DOI：10.1103/physrevb.10.5134 · 被引用次数：459 · 研究领域：Phase-change materials and chalcogenides、Glass properties and applications、Solid-state spectroscopy and crystallography

We report a study of the infrared and Raman spectra of bulk glasses in the binary alloy system ${\mathrm{Ge}}_{1\ensuremath{-}x}{\mathrm{S}}_{x}$ ($0.90\ensuremath{\ge}x\ensuremath{\le}0.55$). The spectra are interpreted in terms of models based on covalent bonding in which the $8\ensuremath{-}N$ rule is satisfied; i.e., models in which the Ge atoms are fourfold coordinated and the S atoms are twofold coordinated. For the compound composition Ge${\mathrm{S}}_{2}$, $x=0.67$, the spectra are interpreted in terms of a chemically ordered network in which the element of local order is a tetrahedral arrangement of S atoms about a central Ge atom. For the S-rich alloys, $0.90\ensuremath{\ge}x>0.67$, the data support a generalized chain-crossing model (CCM) rather than a random-covalent-network model (RCNM). The generalized CCM allows for a second species of ${\mathrm{S}}_{8}$ rings to be in solution with a Ge-S network. The ${\mathrm{S}}_{8}$ ring fraction shows a sharp increase in concentration for $x>0.80$ indicating that on the average only one to two S atoms are incorporated between the Ge Sites of the network component. For Ge-rich alloys the more limited experimental data support a restricted network model of Philipp which allows Ge-Ge and Ge-S bonds, but not S-S bonds, rather that a RCNM.