{
  "abstract": "The state of a vacancy in a semiconductor is normally described by the Fermi level alone. In wet-etched, electrochemically processed, or humid silicon and silicon carbide, a vacancy also takes up hydrogen and oxygen from water, in amounts set by pH and electrode potential. We treat both effects together by minimizing the grand potential of a vacancy complex over its charge state and hydrogen/oxygen content. The result is a stability map in Fermi level and hydrogen chemical potential, which the computational hydrogen electrode relates to pH and potential. We parameterize it with spin-polarized density functional theory in 64-atom cells, including the vibrational free energy of bound H and O, for the silicon vacancy, its H, O, and OH complexes, and both vacancies of 3C-SiC. Hydrogen binds cooperatively to the silicon vacancy, which goes directly from bare to fully passivated $V$H$_4$. In contact with water the bare vacancy is never the lowest-energy state. Near neutral pH it binds oxygen from water as the A center, the paramagnetic hydroxyl complex forms below about pH 5 at zero bias, and full passivation to $V$H$_4$ requires cathodic bias. In PBE the Fermi level barely moves these boundaries, because the acceptor levels lie at or above the conduction-band edge. In SiC the first hydrogen binds to the silicon vacancy by 1.97 eV but is unbound at the carbon vacancy (the $Z_{1/2}$ center), so hydrogen from water alone should not passivate it except under cathodic bias.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.33469",
  "author_total": 1,
  "authors": [
    {
      "name": "Abhirup Patra"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/fkd44cwz7tzft.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.33469",
  "fulltext_url": null,
  "id": "fkd44cwz7tzft",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.33469",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "cond-mat.mes-hall"
    ],
    [
      "arxiv",
      "cond-mat.mtrl-sci"
    ],
    [
      "openalex",
      "2208|Silicon and Solar Cell Technologies"
    ]
  ],
  "openalex": "W7223892368",
  "pdf_url": "https://arxiv.org/pdf/2610.33469",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-24",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/fkd44cwz7tzft.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:35:35Z",
      "native_id": "2610.33469",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.33469"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:cond-mat.mes-hall",
      "subfield": "condensed-matter"
    }
  ],
  "title": "Charge state and hydration of vacancies in silicon and silicon carbide in contact with water: A grand-canonical first-principles stability map",
  "title_text": "Charge state and hydration of vacancies in silicon and silicon carbide in contact with water: A grand-canonical first-principles stability map",
  "type": "preprint",
  "updated_at": "2026-10-30T12:35:35Z",
  "url": "https://research.draconitic.com/paper/fkd44cwz7tzft",
  "venue": "arXiv",
  "versions": []
}