Electronic structure of tetragonal LaCuO3 studied by photoemission and x-ray-absorption spectroscopy

The electronic structure of the formally Cu3+ metallic LaCuO3 has been studied by photoemission and x-ray-absorption spectroscopy. By analyzing the valence-band and Cu 2p core-level photoemission spectra using a CuO6 cluster model, the charge-transfer energy is estimated to be -1 eV, indicating that the ground state is dominated by the d(9) (L) under bar configuration with which the d(8) configuration is strongly hybridized, where (L) under bar denotes a ligand hole. However, agreement between the experimental results and the cluster-model calculations is not satisfactory for the detailed line shape of the main peaks. Especially, the Cu 2p x-ray-absorption spectrum cannot be well explained by the single-site cluster-model calculation, suggesting the importance of intercluster interaction. On the other hand, the existence of the charge-transfer satellite in the Pauli-paramagnetic state is explained by Hartree-Fock band-structure and self-energy calculations using parameters deduced from the analysis of the photoemission spectra. [S0163-1829(98)00315-4].