Electronic structure of the hole-doped delafossite oxides CuCr 1-xMgxO2

T. Yokobori*, M. Okawa, K. Konishi, R. Takei, K. Katayama, S. Oozono, T. Shinmura, T. Okuda, H. Wadati, E. Sakai, K. Ono, H. Kumigashira, M. Oshima, T. Sugiyama, E. Ikenaga, N. Hamada, T. Saitoh

*Corresponding author for this work

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37 Citations (Scopus)

Abstract

We report the detailed electronic structure of a hole-doped delafossite oxide CuCr1-xMgxO2 (0≤x≤0.03) studied by photoemission spectroscopy (PES), soft x-ray absorption spectroscopy (XAS), and band-structure calculations within the local-density approximation +U (LDA+U) scheme. Cr/Cu 3p-3d resonant PES reveals that the near-Fermi-level leading structure has primarily the Cr 3d character with a minor contribution from the Cu 3d through Cu 3d-O 2p-Cr 3d hybridization, having good agreement with the band-structure calculations. This indicates that a doped hole will have primarily the Cr 3d character. Cr 2p PES and L-edge XAS spectra exhibit typical Cr3+ features for all x, while the Cu L-edge XAS spectra exhibited a systematic change with x. This indicates now that the Cu valence is monovalent at x=0 and the doped hole should have Cu 3d character. Nevertheless, we surprisingly observed two types of charge-transfer satellites that should be attributed to Cu+ (3d10) and Cu2+ (3d9) like initial states in Cu 2p-3d resonant PES spectrum of at x=0, while Cu 2p PES spectra with no doubt shows the Cu+ character even for the lightly doped samples. We propose that these contradictory results can be understood by introducing not only the Cu 4s state, but also finite Cu 3d,4s-Cr 3d charge transfer via O 2p states in the ground-state electronic configuration.

Original languageEnglish
Article number195124
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume87
Issue number19
DOIs
Publication statusPublished - 2013 May 17
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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