{
  "abstract": "Point defects have been successfully utilized in various quantum technologies, serving as quantum qubits for quantum computation, single-photon emitters for quantum communication, and nanoscale sensors for quantum metrology. However, their further development faces key challenges, particularly in discovering and exploring suitable defect-host systems that meet the necessary criteria for quantum applications. Here, using polarization-resolved Raman spectroscopy and terahertz absorption spectroscopy, we discover three distinct chromium-vacancy-induced excitations in the uniaxial antiferromagnetic insulator, Cr$_2$O$_3$. These vacancy-induced excitations have an energy scale of a few tens of millielectronvolts and are twofold degenerate, and the lowest one at 64 $cm^{-1}$ is sharp and sensitive to the external magnetic field along the easy-axis direction, particularly close to the spin-flop regime around 6T, where the mode softens from 64 to 27$cm^{-1}$. Based on the defect supercell first-principles calculations, we interpret the mode at 64 $cm^{-1}$ as a local magnetic excitation of the local moment within the chromium vacancy state. Our results establish that the magnetic defect states in Cr$_2$O$_3$ have potential for quantum applications.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.00801",
  "author_total": 15,
  "authors": [
    {
      "name": "Shangfei Wu"
    },
    {
      "name": "Laur Peedu"
    },
    {
      "name": "Zhihao Wang"
    },
    {
      "name": "Xuecong Wang"
    },
    {
      "name": "Xianghan Xu"
    },
    {
      "name": "Kai Du"
    },
    {
      "name": "Sang-Wook Cheong"
    },
    {
      "name": "Aleksei Boldin"
    },
    {
      "name": "Joosep Link"
    },
    {
      "name": "Ivo Heinmaa"
    },
    {
      "name": "Raivo Stern"
    },
    {
      "name": "Sai Mu"
    },
    {
      "name": "Urmas Nagel"
    },
    {
      "name": "Toomas Rõõm"
    },
    {
      "name": "Girsh Blumberg"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/3151r0qg89aes.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.00801",
  "fulltext_url": null,
  "id": "3151r0qg89aes",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.00801",
  "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.mtrl-sci"
    ],
    [
      "arxiv",
      "cond-mat.str-el"
    ],
    [
      "openalex",
      "3104|Advanced Condensed Matter Physics"
    ]
  ],
  "openalex": "W7206175233",
  "pdf_url": "https://arxiv.org/pdf/2609.00801",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-01",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/3151r0qg89aes.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:18:00Z",
      "native_id": "2609.00801",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.00801"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:cond-mat.mtrl-sci",
      "subfield": "condensed-matter"
    }
  ],
  "title": "Magnetic quantum defects in a uniaxial antiferromagnetic insulator",
  "title_text": "Magnetic quantum defects in a uniaxial antiferromagnetic insulator",
  "type": "preprint",
  "updated_at": "2026-10-30T12:18:00Z",
  "url": "https://research.draconitic.com/paper/3151r0qg89aes",
  "venue": "arXiv",
  "versions": []
}