The Chemical Bonding in Crystals with Chalcopyrite Structure

Abstract
Experimentally with x-ray spectroscopy method and theoretically using the cluster approach of the local coherent potential method the particularities of chemical bonds of the semiconductors AgGaS₂, AgInS₂, CuGaS₂, CuInS₂ have been investigated. The fluorescent x-ray emission K-bands and the absorption K-spectra (XANES) of sulphur in the compounds investigated were obtained with resolution 0.2 eV. For upper part of the valence bands the electron structure is due to the occupied d-states of the noble metal (Ag, Cu), which mix with the delocalized p-states of S. The significant mixture of these states shows the strong covalent bond of S atom with noble metal atom.'The three maxima splitting of these states confirms the resonance character of the interaction of these atoms. The similarity of results for both chalcopyrite and zinc-blend stuctures proves, that the short-range ordering determines the electronic energy structure of these tetrahedral semiconductors.