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DF: Dielektrische Festkörper

DF 7: Poster

DF 7.6: Poster

Mittwoch, 26. März 2003, 14:30–18:00, P2a

Electronic Structure of Sn₂P₂S₆ — •A. Selinger¹, K. Kuepper¹, A.V. Postnikov^1,2, V. Caciuc^1,3, A. Ruediger⁴, A.A. Grabar⁵, Yu.M. Vysochanskii⁵, and M. Neumann¹ — ¹Fachbereich Physik, Barbarastr. 7, Universität Osnabrück, D-49069 Osnabrück — ²Institute of Metal Physics, S. Kowalewskoj 18, 620219 Yekaterinburg, Russia — ³Institut für Festkörperforschung, Forschungszentrum Jülich, D-52425 Jülich, Germany — ⁴University of Cambridge, Department of Earth Sciences, Downing Street, Cambridge CB2 3EQ, United Kingdom — ⁵Uzhgorod University, Pidhirna 46, 88000 Uzhgorod, Ukraine

Tin-hypothiodiphosphate (Sn₂P₂S₆) is a ferroelectric compound with remarkable photorefractive properties [1,2]. We investigated the electronic structure of Sn₂P₂S₆ by x-ray photoelectron spectroscopy and soft x-ray fluorescence spectroscopy in combination with theoretical first-priciple electronic calculations. Excellent agreement between theory and experiment data for the electronic structure of the investigated compound is achieved. With help of the Sn core level spectra it is confirmed that the compound contains Sn²⁺-ions. The valence band mainly consists of five resolvable bands between 3.3 eV and 14.5 eV. Sn₂P₂S₆ can be viewed as an ionic crystal, built of Sn²⁺ and the (P₂S₆)⁴⁻ clusters. Inside the cluster, P–P and P–S bonds are largely covalent and characterized by sp-hybridization.

[1] A.A. Grabar et al., Opt. Commun. 188, 187 (2001), [2]A. Shumelyuk et al., Appl. Phys. B 72, 707 (2001)