We have studied the electronic structure of A -site ordered perovskite oxides ACu3V4O12 (A=Na, Ca, and Y) using photoemission spectroscopy. V and Cu valence fluctuations are clearly observed in the V2p and the Cu2p core-level spectra. In going from A=Na to Ca to Y, electrons doped by the A -site substitution are mainly captured by the Cu site which has a mixture of +2 (d9) and +3 (d9 L, L is an O2p hole) and are partly distributed into the V site. The photoemission spectra near the Fermi level show a systematic change induced by the A -site substitution. The electronic structure of ACu3V4O12 is very different from that in Ca1-xSrxVO3 due to the existence of the Cu 3d electrons, and the unusual correlation effect in ACu 3V4O12 can be related to the valence fluctuations observed in the core-level spectra.
|Physical Review B - Condensed Matter and Materials Physics
|Published - 2010 Apr 20
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics