Cu 2p X-ray absorption and Cu 2p-3d resonant photoemission spectroscopy of LaCuO₃

In order to study the effect of intercluster interaction on the high-energy spectroscopy of formally Cu³⁺ oxides, we have performed X-ray absorption spectroscopy (XAS) and Cu 2p-3d resonant photoemission spectroscopy (RPES) studies of rhombohedrally distorted LaCuO₃. In the Cu 2p XAS spectrum, the Cu 2p_3/2 main peak is split into two structures, indicating that the interaction between the CuO₆ octahedral clusters is strong. The valence-band RPES spectrum shows an enhanced satellite structure at ∼ 12.5 eV, similar to that of Cu²⁺ oxides for the incident photon energies which create intermediate states well screened by the intercluster interaction. For the incident photon energy for the poorly screened intermediate state, the enhanced satellite structure becomes broad and has a maximum at ∼ 13 eV.