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Chemical Short-Range Order in Selenide and Telluride Glasses

DOI: 10.1021/acs.jpcb.6b05996 DOI Help

Authors: Ildikó Pethes (Wigner Research Centre for Physics, Hungarian Academy of Sciences) , Radwan Chahal (Institut Sciences Chimiques de Rennes) , Virginie Nazabal (Institut Sciences Chimiques de Rennes) , Carmelo Prestipino (Institut Sciences Chimiques de Rennes) , Angela Trapananti (CNR, Istituto Officina dei Materiali, OGG c/o ESRF) , Stefan Michalik (Diamond Light Source) , Pál Jóvári (Wigner Research Centre for Physics, Hungarian Academy of Sciences)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: The Journal Of Physical Chemistry B , VOL 120 , PAGES 9204 - 9214

State: Published (Approved)
Published: September 2016
Diamond Proposal Number(s): 12163

Open Access Open Access

Abstract: The structure of Ge20SbxSe80–x (x = 5, 15, 20) glasses was investigated by neutron diffraction, X-ray diffraction, and extended X-ray fine structure measurements at the Ge, Sb, and Se K-edges. For each composition, large-scale structural models were obtained by fitting simultaneously the experimental data sets in the framework of the reverse Monte Carlo simulation technique. It was found that the structures of these glasses can be described mostly by the chemically ordered network model. Ge–Se and Sb–Se bonds are preferred; Se–Se bonds in the Se-poor composition (x = 20) and M–M (M = Ge, Sb) bonds in strongly Se-rich glass (x = 5) are not needed. The quality of the fits was significantly improved by introducing Ge–Ge bonding in the nearly stoichiometric composition (x = 15), showing a violation of chemical ordering. The structure of Ge20SbxSe80–x was compared to that of several glasses from the three analogous systems (Ge–As–Se, Ge–As–Te, Ge–Sb–Te), and it was found that chemical short-range order becomes more pronounced upon substituting As with Sb and Se with Te. Ge–As–Se glasses behave as random covalent networks over a very broad composition range. Chemical short-range order and disorder coexist in both Te-rich and Te-poor Ge–As–Te glasses, whereas amorphous Ge14Sb29Te57 and Ge22Sb22Te56 are governed by strict chemical preferences.

Subject Areas: Materials, Physics, Chemistry

Instruments: I12-JEEP: Joint Engineering, Environmental and Processing

Other Facilities: ESRF Grenoble (France)