title: Structural and Topological Evolution in SixSe1-xGlasses: Results from 1D and 2D29Si and77Se NMR Spectroscopy.
abstract: The coordination environments of Si and Se atoms and their connectivity in binary SixSe1-xglasses with 0.05 ≤ x ≤ 0.33 are investigated using a combination of one- and two-dimensional29Si and77Se nuclear magnetic resonance (NMR) and Raman spectroscopy. The high-resolution correlated isotropic and anisotropic29Si and77Se NMR spectra allow for the identification and quantitation of a variety of Si and Se environments. The results suggest that the structure of these glasses are characterized by a network with essentially perfect short-range chemical order, but with strong clustering at the intermediate range. Initial addition of Si to Se results in cross-linking of Se chain segments with nanoclusters of corner- and edge-shared SiSe4/2tetrahedra. These clusters percolate via coalescence near x ≥ 0.2 to finally form a low-dimensional network with high molar volume, at the stoichiometric composition (x = 0.33) that is composed of chains of edge-sharing tetrahedra cross-linked by corner-shared tetrahedra. This structural evolution is shown to be consistent with the compositional variation of the glass transition temperature and the molar volume of these glasses.
authors.affiliation: Department of Materials Science & Engineering, University of California at Davis , Davis, California 95616, United States.
authors.forename: M A T
authors.initials: MAT
authors.lastname: Marple
authors.affiliation: Center of Interdisciplinary Magnetic Resonance, National High Magnetic Field Laboratory , 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, United States.
authors.forename: I
authors.initials: I
authors.lastname: Hung
authors.affiliation: Center of Interdisciplinary Magnetic Resonance, National High Magnetic Field Laboratory , 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, United States.
authors.forename: Z
authors.initials: Z
authors.lastname: Gan
authors.affiliation: Department of Materials Science & Engineering, University of California at Davis , Davis, California 95616, United States.
authors.forename: S
authors.identifier: 0000-0002-4504-3632
authors.initials: S
authors.lastname: Sen