Valence band photoemission study of the copper chalcogenide compounds, Cu2S, Cu2Se and Cu2Te

The electronic structures of the copper chalcogenide compounds, Cu2S, Cu2Se and Cu2Te have been investigated by taking photoemission data with synchrotron photon sources. The band calculations are done using the full-potential linear-muffin-tin-orbital method. Since the crystal structures are not clarified well, several simplified structure models are used. The calculated densities of states are compared with the observed spectra. The analysis shows that a sharp peak at -3.5 eV is due to the Cu 3d states, and that the tails at the high and low energy sides of the Cu 3d peak are due to the chalcogen p states. (C) 2003 Elsevier Ltd. All rights reserved.