title: Impact of ⁷⁷Te on the structure and Se NMR spectra of Se-rich Ge-Te-Se glasses: a combined experimental and computational investigation.
abstract: Selenium-rich Ge-Te-Se glasses have been synthesized along the GeSe4-GeTe4 pseudo-composition line and acquired by (77)Se Hahn echo magic-angle spinning NMR. The comparison with the GeSe4 spectrum shows a drastic modification of the typical double-resonance lineshape even at low Te concentrations (<10%). In order to rationalize this feature and to understand the effect of Te on the structure of our glasses, first-principles molecular dynamics simulations and gauge including projector augmented wave NMR parameter calculations have been performed. The distribution of the tellurium atoms in the selenium phase was shown to be mainly responsible for the (77)Se lineshape changes. Another possible factor related to the perturbation of the δiso value due to Te proximity appears to be much more limited in the bulk, while the results obtained using molecular models suggest shifts of several hundreds of ppm.
authors.affiliation: Institut des Sciences Chimiques de Rennes, UMR-CNRS 6226, Ecole Nationale Supérieure de Chimie de Rennes, 35708 Rennes, France. eric.furet@ensc-rennes.fr.
authors.forename: Lila
authors.initials: L
authors.lastname: Bouëssel du Bourg
authors.affiliation: Institut des Sciences Chimiques de Rennes, UMR-CNRS 6226, Université de Rennes 1, 35042 Rennes cedex, France.
authors.forename: Claire
authors.initials: C
authors.lastname: Roiland
authors.affiliation: Institut des Sciences Chimiques de Rennes, UMR-CNRS 6226, Ecole Nationale Supérieure de Chimie de Rennes, 35708 Rennes, France. eric.furet@ensc-rennes.fr.
authors.forename: Laurent
authors.initials: L
authors.lastname: le Pollès
authors.affiliation: CNRS, CEMHTI UPR 3079, University Orléans, 45071 Orléans, France.
authors.forename: Michaël
authors.initials: M
authors.lastname: Deschamps
authors.affiliation: Institut des Sciences Chimiques de Rennes, UMR-CNRS 6226, Université de Rennes 1, 35042 Rennes cedex, France.
authors.forename: Catherine
authors.initials: C
authors.lastname: Boussard-Plédel
authors.affiliation: Institut des Sciences Chimiques de Rennes, UMR-CNRS 6226, Université de Rennes 1, 35042 Rennes cedex, France.
authors.forename: Bruno
authors.initials: B
authors.lastname: Bureau
authors.affiliation: Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK.
authors.forename: Chris J
authors.initials: CJ
authors.lastname: Pickard
authors.affiliation: Institut des Sciences Chimiques de Rennes, UMR-CNRS 6226, Ecole Nationale Supérieure de Chimie de Rennes, 35708 Rennes, France. eric.furet@ensc-rennes.fr.
authors.forename: Eric
authors.initials: E
authors.lastname: Furet