{
  "abstract": "Epitaxial all‐nitride Josephson junctions are promising components for high coherence superconducting qubits, yet nanoscale defects often limit their performance. The key to mitigating these defects lies in understanding the atomic‐scale relationship between polymorph selection, defect chemistry, and device performance. Here, we investigate structural and chemical defects in epitaxially grown 𝛿‐NbN/AlN/𝛿‐NbN, 𝛾‐Nb4N3/AlN/𝛾‐Nb4N3, β‐Nb2N/AlN/β‐Nb2N heterostructures on c‐plane sapphire using molecular beam epitaxy. Advanced microscopy integrated with density functional theory shows varying impurity distribution across different polymorphs. The chemical distribution reveals that δ‐NbN electrodes contain significant oxygen, whereas in β‐Nb2N/AlN/β‐Nb2N heterostructures oxygen preferentially segregates to the AlN barrier. DFT calculations indicate that these differences arise from phase‐dependent oxygen energetics and diffusion kinetics, with oxygen remaining kinetically trapped in δ‐NbN while exhibiting greater mobility in β‐Nb2N. These structural and chemical differences are consistent with the distinct transport behavior observed in the two junction architectures and provide mechanistic insight into the role of defect chemistry in epitaxial nitride Josephson junctions. The observed impurity distribution may influence superconducting properties and contribute to the formation of two‐level systems, a major source of loss and decoherence in superconducting quantum circuits.",
  "abstract_shown": true,
  "affiliations": [
    "Department of Materials Design and Innovation University At Buffalo Buffalo New York USA",
    "Department of Physics and Astronomy Stony Brook University Stony Brook New York USA",
    "Institute For Advanced Computational Science Stony Brook University Stony Brook New York USA",
    "Department of Electrical and Computer Engineering Yale University New Haven Connecticut USA",
    "Department of Materials Science and Engineering Cornell University Ithaca New York USA",
    "School of Electrical and Computer Engineering Cornell University Ithaca New York USA",
    "Kavli Institute at Cornell for Nanoscale Physics Cornell University Ithaca New York USA",
    "School of Applied and Engineering Physics Cornell University Ithaca New York USA",
    "Center For Computational Quantum Physics Flatiron Institute New York USA"
  ],
  "article_type": "research article",
  "arxiv": null,
  "author_total": 11,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Prachi Garg",
      "orcid": "0009-0005-7401-2420"
    },
    {
      "affs": [
        1,
        2
      ],
      "name": "Kedarsh Kaushik"
    },
    {
      "affs": [
        3
      ],
      "name": "Danqing Wang",
      "orcid": "0000-0003-1423-0096"
    },
    {
      "affs": [
        4
      ],
      "name": "Naomi Pieczulewski",
      "orcid": "0000-0003-3455-4282"
    },
    {
      "affs": [
        4
      ],
      "name": "Anand Ithepalli"
    },
    {
      "affs": [
        4
      ],
      "name": "John Wright"
    },
    {
      "affs": [
        4,
        5,
        6
      ],
      "name": "Debdeep Jena"
    },
    {
      "affs": [
        6,
        7
      ],
      "name": "David A. Muller",
      "orcid": "0000-0003-4129-0473"
    },
    {
      "affs": [
        3
      ],
      "name": "Hong X. Tang",
      "orcid": "0000-0001-5374-2137"
    },
    {
      "affs": [
        1,
        8
      ],
      "name": "Cyrus Dreyer",
      "orcid": "0000-0003-0035-7520"
    },
    {
      "affs": [
        0
      ],
      "name": "Baishakhi Mazumder",
      "orcid": "0000-0003-1748-5297"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/5jrmstskr6m9h.bib",
  "cited_by": 0,
  "doi": "10.1002/advs.76944",
  "fulltext_url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC13440214/",
  "id": "5jrmstskr6m9h",
  "issns": [
    "2198-3844"
  ],
  "landing_url": "https://doi.org/10.1002/advs.76944",
  "language": "en",
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "heading",
      "Research Article"
    ],
    [
      "openalex",
      "3103|Superconducting and THz Device Technology"
    ]
  ],
  "openalex": "W7172515162",
  "pdf_url": null,
  "pmcid": "PMC13440214",
  "pmid": "42555291",
  "published": "2026-08-05",
  "publisher": "Wiley",
  "ris": "https://research.draconitic.com/paper/5jrmstskr6m9h.ris",
  "sources": [
    {
      "first_seen": "2026-10-31T12:23:41Z",
      "native_id": "PMC13440214",
      "source": "pmc",
      "url": "https://doi.org/10.1002/advs.76944"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "openalex:3103|Superconducting and THz Device Technology",
      "subfield": "general"
    }
  ],
  "title": "Phase‐Dependent Oxygen Defect Energetics in Epitaxial NbN/AlN/NbN Films",
  "title_text": "Phase‐Dependent Oxygen Defect Energetics in Epitaxial NbN/AlN/NbN Films",
  "type": "peer-reviewed",
  "updated_at": "2026-11-01T12:20:49Z",
  "url": "https://research.draconitic.com/paper/5jrmstskr6m9h",
  "venue": "Advanced Science",
  "versions": []
}