X-ray spectroscopy investigation of the electronic structure of SnSx and Li0.57SnS2 compounds

Photoemission spectroscopy and X-ray emission spectroscopy have been used t o investigate the role of the chemical environment on the electronic struct ure of SnS, SnS2, Sn2S3 and Li0.57SnS2 compounds. For this purpose, we have studied the Sn 3d(5/2) and S 2P(1/2,3/2) inner levels and the valence band by photoemission spectroscopy and the S 3p electronic distributions by X-r ay emission spectroscopy. We have established fingerprints of the Sn-II and Sn-IV valencies in the compounds SnS and SnS2 and have shown that these ar e observed in Sn2S3 where it is known that both II and IV valencies are pre sent. By comparing the data for Li0.57SnS2 with those for the other compoun ds, we have demonstrated that the Sn-II and Sn-IV signatures are also found in this compound. We have thus ascertained experimentally that Sn is parti ally reduced in SnS2 upon Li intercalation. In addition, the data have been found to be in excellent agreement with recent densities of electronic sta tes calculations performed in the framework of the density functional theor y for the same compounds.