Electronic structure of Sn2P2S6

Abstract

The electronic properties of the ferroelectric compound Sn2P2S6 are investigated by x-ray photoelectron spectroscopy and soft x-ray fluorescence spectroscopy. Excellent agreement between theoretical calculations and experimental 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. Consistent with the results of band-structure calculation and the soft x-ray fluorescence spectra, Sn2P2S6 can be viewed as an ionic crystal, built of Sn2+ and the (P2S6)(4-) fragments. Within the latter, P-P and P-S bonds are largely covalent and characterized by sp hybridization.