Electronic structures of SnS and SnS2

Abstract

The electronic structures of SnS and SnS2 have been investigated from first principles calculations to provide a full analysis of the valence and conduction bands. A good agreement with experimental X‐ray photoelectron spectroscopy (XPS), S Kβ X‐ray emission spectroscopy (XES) and X‐ray absorption spectroscopy (XAS) at S K, Sn L1 and Sn L3 edges is found and the main features of the spectra are analysed in terms of chemical bonding. In the case of XAS, we show that core‐hole effect is significant at the S K edge. The origin of the 119Sn Mössbauer parameters has been also investigated. The increase of the isomer shift from SnS2 to SnS is related to the increase of Sn 5s electron population and correlated to the decreasing intensity of the lowest energy peak of the XAS spectra at the Sn L3 edge. The values of the quadrupole splitting evaluated from the electric field gradients at the nucleus are explained from the Sn 5p electron anisotropy. Finally, the effects of interlayer interactions and intralayer local distortion are examined by considering different structural models.