In contrast to ordinary perovskites ABO3, A-site ordered perovskites AA′3B4O12 include transition metals in both A′ and B sites. The A′-O, B-O, and A′-B interactions in A-site ordered perovskites give rise to various physical properties. In this study, we report the O 1s and Cu 2p x-ray absorption spectroscopy (XAS) and resonant x-ray emission spectroscopy (RXES) study on the A-site ordered perovskite ACu3Ru4O12 (A = Na, Ca, and La). Hartree-Fock calculation and cluster model calculation were carried out to analyze O 1s and Cu 2p XAS spectra. The O 1s RXES spectra indicate that the number of O 2p holes increases in going from La to Ca to Na. In addition, the Cu 2p RXES spectra reveal that the charge-transfer (CT) energy decreases in going from La to Ca to Na. The decrease of CT is consistent with our calculations and suggest an increase of the O 2p holes in the ground state. The substitution of the A site ion changes not only the carrier concentration in the Ru 4d and Cu 3d bands but also the O 2p to Cu 3d CT energy.
- A-site ordered perovskite compounds
- Resonant x-ray emission spectroscopy
- Ru oxides
- X-ray absorption Spectroscopy
ASJC Scopus subject areas
- Physics and Astronomy(all)