The paper is published in Physics of the Solid State, 44, No. 9, pp. 1643-1647 (2002).

An EXAFS study of the local structure of the PbxSn1-xS solid solution

A.I. Lebedev, I.A. Sluchinskaya, I.H. Munro

Moscow State University, Vorob'evy gory, Moscow, 119899 Russia
Daresbury Laboratory, Warrington, WA4 4AD UK

The local environment of Pb atoms in the PbxSn1-xS solid solutions with cubic and orthorhombic structure was studied by EXAFS spectroscopy. The shortest Pb-S distance in samples with orthorhombic structure was found to be smaller by 0.2 A than that in cubic-lattice samples, which is a sign of stereochemical activity of the 6s2 lone electron pair of a Pb atom. The metal atom arrangement reveals strong short-range order, which results in the formation of -Pb-Sn-Pb-Sn-... zigzag chains aligned with the c axis (in the Pbnm system) in orthorhombic samples. It was shown that the onset of such short-range order in Pb0.5Sn0.5S can initiate the formation of superstructures belonging to the C2v7 or C2v2 space groups.

Keywords: x-ray absorption spectroscopy, lead tin sulfide sulphide, semiconductor solid solutions, synchrotron radiation


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