Interaction of Cu 3d and O 2p states in Mg1-xCuxO solid solutions with NaCl structure: X-ray photoelectron and x-ray emission study

The electronic structure of the solid solutions Mg1-xCuxO (x= 0.10,0.12,0.1 5,0.20) with the NaCl structure was studied by means of x-ray photoelectro n and soft-x-ray emission spectroscopy (XES). The XES measurements include a study of the fluorescence O K alpha spectra measured at the photon excita tion energy of 550 eV and the electron-excited Cu Lcr spectra. Based on the analysis of the valence-band spectra, the partial Cu 3d states and the par tial O 2p states in the O 2p-Cu 3d(4sp) bond are separated. The distributio n of the partial Cu 3d states in Mg1-xCuxO is similar to that in CuO. The p artial O 2p states in the O 2p-Cu 3d(4sp) bond in Mg1-xCuxO correspond esse ntially to the O 2p states in CuO. That means that the Cu-O interactions pr actically do not depend on the difference in the crystal structures of Mg1- xCuxO and CuO, but are mainly determined by electronic characteristics of a toms. The exchange splitting in the Cu 3s photoemission spectrum is analyze d. It was established that the degree of covalency and the occupancy of Cu 3d states in Mg1-xCuxO solid solutions are less than those in CuO.