X-RAY-SPECTRA AND ELECTRONIC-STRUCTURES OF CUS AND CU2S

The Cu Lalpha emission spectra in fluorescence from CuS and Cu2S are m easured with a two-crystal vacuum spectrometer equipped with beryl cry stals. The measured spectra are composed of a prominent peak and its h igh-energy structure. They are compared with the S L2,3 emission, S Kb eta emission, Cu L3 absorption and S K absorption spectra reported pre viously to obtain information about the electronic structures of the c opper sulfides. It is shown that the valence bands are composed of thr ee parts: The upper part consists of the Cu 3d states with considerabl e contribution of the S 3p and 3s characters, while the middle part co nsists of the S 3p states with small contribution of the Cu 3d and S 3 s characters and the lower part arises from the S 3s states. In additi on, it is shown that the hybridization between the Cu 3d and S 3p or 4 p orbitals is fairly large in the lower part of the conduction band of CuS.