Electronic structure of superconducting inorganic polymer (SN)x

The results of our theoretical and experimental study of electronic structure of poly(sulfur nitride) are presented. The S L-2.3 (3s --> 2p transition) and N K alpha (2p --> 1s transition) X-ray emission spectra (XES) of(SN)(x) single crystal are measured using synchrotron radiation. The experimental spectra are compared with the results of ab-initio TB-LMTO band structure calculations of 3D solid (SN), and molecular (S2N(2))(2) crystals. It is found that the molecular(S2N2)(2) is an insulator with a band gap about 2.7 eV whereas the solid (SN)(x) is metallic. According to the theoretical and experimental information, the S 3p states dominate the density of states (DOS) at the Fermi level and provide the metallic and superconducting properties of this compound. (C) 1999 Elsevier Science B.V. All rights reserved.