Electronic Structure of a Delafossite Oxide CuAlO2 in Comparison with CuCrO2
Abstract
We investigated the electronic structure of a delafossite oxide CuAlO2 in comparison with CuCrO2, using vacuum ultraviolet (VUV) and hard x-ray (HX) photoemission spectroscopy (PES) and band structure calculations within the local-density approximation +U scheme. Cu 3p − 3d resonant PES and Cu 2p core-level HX-PES give concrete evidence that the Cu valence in CuAlO2 is monovalent, which makes a sharp contrast to CuCrO2 that showed contradictory results depending upon probing methods [Yokobori \textit{et al.}, Phys. Rev. B \textbf{87}, 195124 (2013)]. We further noticed weak but detectable satellite structures due to Cu2+ state in the Cu 2p HX-PES spectrum of CuCrO2, surprisingly, without an observable main peak due to the Cu2+ state. Comparisons between the valence-band HX-PES spectra and the band structure calculations revealed a significant amount of the Cu 4s and Al 3s/Cr 4s states in the valence band. The above results can reasonably be explained by the Cu $3d, 4s-$Cr 3d charge transfer model that we previously proposed in the above paper, thereby demonstrating the critical role of empty 3d orbitals in the electronic structure of the copper delafossite oxides.
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BibTeX
@misc{takahashi2026electronic,
title = {{Electronic Structure of a Delafossite Oxide CuAlO$_2$ in Comparison with CuCrO$_2$}},
author = {Kenta Takahashi and Ryo Kato and Mario Okawa and Tetsuji Okuda and Akira Yasui and Eiji Ikenaga and Kanta Ono and Noriaki Hamada and Tomohiko Saitoh},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.16061},
eprint = {2610.16061},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.16061},
}
RIS
TY - UNPB
TI - Electronic Structure of a Delafossite Oxide CuAlO_2 in Comparison with CuCrO_2
AU - Kenta Takahashi
AU - Ryo Kato
AU - Mario Okawa
AU - Tetsuji Okuda
AU - Akira Yasui
AU - Eiji Ikenaga
AU - Kanta Ono
AU - Noriaki Hamada
AU - Tomohiko Saitoh
PY - 2026
DA - 2026/10/12
PB - arXiv
DO - 10.48550/arxiv.2610.16061
UR - https://arxiv.org/abs/2610.16061
AB - We investigated the electronic structure of a delafossite oxide CuAlO_2 in comparison with CuCrO_2, using vacuum ultraviolet (VUV) and hard x-ray (HX) photoemission spectroscopy (PES) and band structure calculations within the local-density approximation +U scheme. Cu 3p − 3d resonant PES and Cu 2p core-level HX-PES give concrete evidence that the Cu valence in CuAlO_2 is monovalent, which makes a sharp contrast to CuCrO_2 that showed contradictory results depending upon probing methods [Yokobori \textit{et al.}, Phys. Rev. B \textbf{87}, 195124 (2013)]. We further noticed weak but detectable satellite structures due to Cu^2+ state in the Cu 2p HX-PES spectrum of CuCrO_2, surprisingly, without an observable main peak due to the Cu^2+ state. Comparisons between the valence-band HX-PES spectra and the band structure calculations revealed a significant amount of the Cu 4s and Al 3s/Cr 4s states in the valence band. The above results can reasonably be explained by the Cu $3d, 4s-$Cr 3d charge transfer model that we previously proposed in the above paper, thereby demonstrating the critical role of empty 3d orbitals in the electronic structure of the copper delafossite oxides.
ER -