{
  "abstract": "Superconductivity in graphite intercalation compounds requires occupancy of a carbon-derived interlayer band filled by charge from an electropositive intercalant. Bis-hexahapto (eta6-eta6) coordination binds transition metals covalently to two graphene sheets with little charge transfer: the mechanism defining this chemistry removes the donation that superconductivity rests on. We ask, for group-6 Cr, Mo and W in bilayer graphene, whether Fermi-level states retain the interstitial, carbon-p character of ionic references, with bulk CaC6 and same-cell C12Ca/C12Li controls. Electron-phonon coupling is not computed. At one metal per gallery (C12M), the ionic controls retain 68 and 45 per cent of gallery spectral weight in atom-masked interstitial regions at EF; the group-6 systems retain 15, 22 and 23 per cent. The contrast is compositional: group-6 galleries carry more absolute interstitial weight than C12Li, but projected density of states within +/-0.15 eV of EF is carbon dominated in the ionic references and metal dominated (~73 per cent, of which 89-98 per cent is d) in all three group-6 bilayers. Every system studied is metallic; they differ in what carries the Fermi surface. Zone-centre phonons are clean for all three ordered bilayers; the pristine AA bilayer is not, its unstable mode being the AA-to-AB shear. Geometrically, eta6-eta6 coordination requires AA stacking and reverses the intrinsic Bernal preference by 400-600 meV wherever metal is present. Ordered phases are metastable against bulk metal (+2.9-5.0 eV per atom) but bound against isolated atoms (-1.6-4.1 eV); instability ordering (Cr least, W most) matches Cr > Mo > W reactivity. C12Cr is metallic; tungsten alone carries 0.65 muB. Bis-hexahapto intercalation delivers strong interlayer bonding and a definite AA registry, but not the interlayer-band character of superconducting graphite intercalation compounds.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.00083",
  "author_total": 1,
  "authors": [
    {
      "name": "Mingguang Chen"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/665xasadaey9x.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.00083",
  "fulltext_url": null,
  "id": "665xasadaey9x",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.00083",
  "language": null,
  "licence": "CC-BY-NC-SA-4.0",
  "licence_label": "CC BY-NC-SA 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by-nc-sa/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "cond-mat.mtrl-sci"
    ],
    [
      "openalex",
      "2505|Graphene research and applications"
    ]
  ],
  "openalex": "W7206158933",
  "pdf_url": "https://arxiv.org/pdf/2609.00083",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-07",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/665xasadaey9x.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:19:48Z",
      "native_id": "2609.00083",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.00083"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:cond-mat.mtrl-sci",
      "subfield": "condensed-matter"
    }
  ],
  "title": "Fermi-Level Metal-d Character of Group-6 Bis-Hexahapto Bilayer Graphene",
  "title_text": "Fermi-Level Metal-d Character of Group-6 Bis-Hexahapto Bilayer Graphene",
  "type": "preprint",
  "updated_at": "2026-10-30T12:19:48Z",
  "url": "https://research.draconitic.com/paper/665xasadaey9x",
  "venue": "arXiv",
  "versions": []
}