title: Structure of amorphous GeSe9 by neutron diffraction and first-principles molecular dynamics: Impact of trajectory sampling and size effects.
abstract: The structure of glassy GeSe9 was investigated by combining neutron diffraction with density-functional-theory-based first-principles molecular dynamics. In the simulations, three different models of N = 260 atoms were prepared by sampling three independent temporal trajectories, and the glass structures were found to be substantially different from those obtained for models in which smaller numbers of atoms or more rapid quench rates were employed. In particular, the overall network structure is based on Sen chains that are cross-linked by Ge(Se4)1/2 tetrahedra, where the latter are predominantly corner as opposed to edge sharing. The occurrence of a substantial proportion of Ge-Se-Se connections does not support a model in which the material is phase separated into Se-rich and GeSe2-rich domains. The appearance of a first-sharp diffraction peak in the Bhatia-Thornton concentration-concentration partial structure factor does, however, indicate a non-uniform distribution of the Ge-centered structural motifs on an intermediate length scale.
authors: Institut de Physique et de Chimie des Matériaux de Strasbourg, 23 rue du Loess, BP 43, F-67034 Strasbourg Cedex 2, France.
authors: Sébastien
authors: S
authors: Le Roux
authors: Chaire de Simulation à l'Echelle Atomique (CSEA), Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
authors: Assil
authors: A
authors: Bouzid
authors: Department of Materials Science and Engineering, Seoul National University, Seoul 151-744, Korea.
authors: Kye Yeop
authors: KY
authors: Kim
authors: Department of Materials Science and Engineering, Seoul National University, Seoul 151-744, Korea.
authors: Seungwu
authors: S
authors: Han
authors: Department of Physics, University of Bath, Bath BA2 7AY, United Kingdom.
authors: Anita
authors: A
authors: Zeidler
authors: Department of Physics, University of Bath, Bath BA2 7AY, United Kingdom.
authors: Philip S
authors: PS
authors: Salmon
authors: Institut de Physique et de Chimie des Matériaux de Strasbourg, 23 rue du Loess, BP 43, F-67034 Strasbourg Cedex 2, France.
authors: Carlo
authors: C
authors: Massobrio