Atomic level structure of Ge-Sb-S glasses: Chemical short range order and long Sb-S bonds

JOURNAL OF ALLOYS AND COMPOUNDS

卷:774

Article

Pethes, I¹  Nazabal, V^2,3  Ari, J.^2,4  Kaban, I⁵  Darpentigny, J.⁶  Welter, E.⁷  Gutowski, O.⁷  Bureau, B.²  Messaddeq, Y.⁴  Jovari, P.¹ 

[1] Hungarian Acad Sci, Wigner Res Ctr Phys, POB 49, H-1525 Budapest, Hungary

[2] Univ Rennes 1, UMR CNRS 6226, Inst Sci Chim Rennes, Campus Beaulieu, F-35042 Rennes, France

[3] Univ Pardubice, Fac Chem Technol, Dept Graph Arts & Photophys, Studentska 573, Pardubice 53210, Czech Republic

[4] Univ Laval, COPL, 2375 Rue Terrasse, Quebec City, PQ, Canada

[5] IFW Dresden, Inst Complex Mat, Helmholtzstr 20, D-01069 Dresden, Germany

[6] CEA Saclay, Lab Leon Brillouin, F-91191 Gif Sur Yvette, France

[7] DESY, Notkestr 85, D-22607 Hamburg, Germany

关键词: Chalcogenide glasses;    Ge-Sb-S;    Structure;    Diffraction;    EXAFS;    RMC;   

DOI  :  10.1016/j.jallcom.2018.09.334

来源: Elsevier

【 摘 要 】

The structure of Ge20Sb10S70, Ge23Sb12S65 and Ge26Sb13S61 glasses was investigated by neutron diffraction (ND), X-ray diffraction (XRD), extended X-ray absorption fine structure (EXAFS) measurements at the Ge and Sb K-edges as well as Raman scattering. For each composition, large scale structural models were obtained by fitting simultaneously diffraction and EXAFS data sets in the framework of the reverse Monte Carlo (RMC) simulation technique. Ge and S atoms have 4 and 2 nearest neighbors, respectively. The structure of these glasses can be described by the chemically ordered network model: Ge-S and Sb-S bonds are always preferred. These two bond types adequately describe the structure of the stoichiometric glass while S-S bonds can also be found in the S-rich composition. Raman scattering data show the presence of Ge-Ge, Ge-Sb and Sb-Sb bonds in the S-deficient glass but only Ge-Sb bonds are needed to fit diffraction and EXAFS datasets. A significant part of the Sb-S pairs has 0.3-0.4 angstrom longer bond distance than the usually accepted covalent bond length (similar to 2.45 angstrom). From this observation it was inferred that a part of Sb atoms have more than 3 S neighbors. (C) 2018 Elsevier B.V. All rights reserved.

【 授权许可】

Free