{
  "abstract": "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 3$p\\! -\\! 3d$ 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.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": "Journal reference: Journal of the Physical Society of Japan 88, 074701 (2019)",
  "arxiv": "2610.16061",
  "author_total": 9,
  "authors": [
    {
      "name": "Kenta Takahashi"
    },
    {
      "name": "Ryo Kato"
    },
    {
      "name": "Mario Okawa"
    },
    {
      "name": "Tetsuji Okuda"
    },
    {
      "name": "Akira Yasui"
    },
    {
      "name": "Eiji Ikenaga"
    },
    {
      "name": "Kanta Ono"
    },
    {
      "name": "Noriaki Hamada"
    },
    {
      "name": "Tomohiko Saitoh"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/6a0n8s31a3g62.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.16061",
  "fulltext_url": null,
  "id": "6a0n8s31a3g62",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.16061",
  "language": null,
  "licence": "LicenseRef-arXiv-nonexclusive-1.0",
  "licence_label": "arXiv licence",
  "licence_source": "article",
  "licence_url": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "cond-mat.str-el"
    ],
    [
      "openalex",
      "2505|Electronic and Structural Properties of Oxides"
    ]
  ],
  "openalex": "W7208367811",
  "pdf_url": "https://arxiv.org/pdf/2610.16061",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-12",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/6a0n8s31a3g62.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:29:06Z",
      "native_id": "2610.16061",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.16061"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:cond-mat.str-el",
      "subfield": "condensed-matter"
    }
  ],
  "title": "Electronic Structure of a Delafossite Oxide CuAlO$_2$ in Comparison with CuCrO$_2$",
  "title_text": "Electronic Structure of a Delafossite Oxide CuAlO_2 in Comparison with CuCrO_2",
  "type": "preprint",
  "updated_at": "2026-10-30T12:29:06Z",
  "url": "https://research.draconitic.com/paper/6a0n8s31a3g62",
  "venue": "arXiv",
  "versions": [
    {
      "doi": "10.7566/jpsj.88.074701",
      "pid": null,
      "relation": "published-as",
      "title": null,
      "venue": null
    }
  ]
}