{
  "abstract": "$η$ pairing describes a staggered superconducting condensate whose order parameter changes sign between neighboring unit cells while maintaining a uniform magnitude. Nearly four decades after its theoretical proposal by C. N. Yang, a material platform for stabilizing $η$ pairing has remained elusive. Here, we reveal that altermagnetism, despite being pair breaking for conventional BCS pairing, naturally favors $η$-like pairing in V$_2$Se$_2$O-family altermagnets. Their valley-contrasting spin structure gives rise to oppositely spin-polarized, symmetry-related valleys centered at $X=(π,0)$ and $Y=(0,π)$, which form spin-singlet pairing partners separated by the commensurate momentum $\\mathbf Q=(π,π)$, thereby favoring an $η$-like condensate. Self-consistent calculations demonstrate that the resulting $η$-like state remains robust over broad variations of chemical potential, hopping parameters, and Fermi-surface topology. To detect this hidden staggered order, we propose a phase-sensitive Josephson measurement with a uniform superconductor, where destructive interference suppresses single-Cooper-pair tunneling while preserving two-Cooper-pair processes. This constitutes a charge-$4e$-like Josephson response despite a bulk condensate composed of charge-$2e$ Cooper pairs, providing a direct phase-sensitive signature of the otherwise elusive $η$-like condensate in V$_2$Se$_2$O-family altermagnets.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.22935",
  "author_total": 4,
  "authors": [
    {
      "name": "Chun Yu Wan"
    },
    {
      "name": "Xiangxi Zhang"
    },
    {
      "name": "Fei Yang"
    },
    {
      "name": "Junwei Liu"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/axm38cc3ch6yh.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.22935",
  "fulltext_url": null,
  "id": "axm38cc3ch6yh",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.22935",
  "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.supr-con"
    ],
    [
      "openalex",
      "3104|Physics of Superconductivity and Magnetism"
    ]
  ],
  "openalex": "W7222955130",
  "pdf_url": "https://arxiv.org/pdf/2610.22935",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-16",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/axm38cc3ch6yh.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:30:32Z",
      "native_id": "2610.22935",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.22935"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:cond-mat.supr-con",
      "subfield": "condensed-matter"
    }
  ],
  "title": "Hidden Staggered Superconducting Order in V2Se2O-Family Altermagnets",
  "title_text": "Hidden Staggered Superconducting Order in V2Se2O-Family Altermagnets",
  "type": "preprint",
  "updated_at": "2026-10-30T12:33:28Z",
  "url": "https://research.draconitic.com/paper/axm38cc3ch6yh",
  "venue": "arXiv",
  "versions": []
}