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Electronic structure of Cu 2 O and CuO

1988; American Physical Society; Volume: 38; Issue: 16 Linguagem: Inglês

10.1103/physrevb.38.11322

1095-3795

J. Ghijsen, L. H. Tjeng, J. van Elp, Henk Eskes, J. Westerink, G. A. Sawatzky, M. T. Czyżyk,

Electronic and Structural Properties of Oxides

The electronic structure of copper oxides has been investigated by photoelectron (x-ray photoemission, ultraviolet photoemission), Auger electron, and bremsstrahlung isochromat spectroscopies. The experimental results are compared with one-electron band-structure calculations as well as with a cluster configuration interaction model. It is demonstrated that the results for ${\mathrm{Cu}}_{2}$O agree well with band theory, whereas those for CuO clearly show strong deviations which we argue are due to electron-correlation effects in the open-shell $d$ bands. From the comparison to cluster calculations we extract values for the $\mathrm{Cu} d\ensuremath{-}d$ and $\mathrm{O} p\ensuremath{-}p$ Coulomb interactions, the O to Cu charge transfer energy, and the degree of $\mathrm{Cu} d\ensuremath{-}\mathrm{O} 2p$ hybridization. From this we demonstrate that CuO is a charge-transfer gap insulator.