{
  "abstract": "\"Infinite layer\" nickelates ${\\cal R}$NiO$_2$ (${\\cal R}$=rare earth), having empty apical O sites, become superconducting upon hole doping, stimulating research into the related sequence Nd$_{n+1}$Ni$^{+p}_n$O$_{2n+2}$, formal charge state $p$=1+$\\frac{1}{n}$, $n$=2,3,4,...., with the $n$=5 member being found to be superconducting. The two layer system La$_3$Ni$_2$O$_{7-δ}$, with $δ$=0,$\\frac{1}{2}$,1 ($p$=2.5,2,1.5) approaches the peak in the nickelate superconducting dome but shows no superconductivity. Newly reported La$_3$Ni$_2$O$_5$F reaches the Ni$^{1+}$ goal while, as we show, introducing a partially occupied electron band $E^*$, based on an interstitial density that extends over the three open \"apical\" layers and leads to a single cylindrical electron Fermi surface giving self-doping. The commonly inert Ni $d_{xz},d_{yz}$ orbitals partner with interstitial $E^*$ to provide an incipient non-analytic Dirac point, with the critical point being reachable by pressure or further F insertion. The $E^*$ electron cylinder and the conventional Ni $dpσ$ hole carriers combine to provide a two-fluid dichotomy of hole and electron quasiparticles, affecting normal state properties that should verify the dichotomous aspect of transport.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2606.10564",
  "author_total": 3,
  "authors": [
    {
      "name": "Young-Joon Song"
    },
    {
      "name": "K. -W. Lee"
    },
    {
      "name": "W. E. Pickett"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/c7cmpc6nvgtx3.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2606.10564",
  "fulltext_url": null,
  "id": "c7cmpc6nvgtx3",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2606.10564",
  "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.mtrl-sci"
    ],
    [
      "arxiv",
      "cond-mat.supr-con"
    ],
    [
      "openalex",
      "3104|Physics of Superconductivity and Magnetism"
    ]
  ],
  "openalex": "W7164154023",
  "pdf_url": "https://arxiv.org/pdf/2606.10564",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-27",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/c7cmpc6nvgtx3.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:35:50Z",
      "native_id": "2606.10564",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2606.10564"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:cond-mat.mtrl-sci",
      "subfield": "condensed-matter"
    }
  ],
  "title": "Dichotomous electronic system in a bilayer Ni$^{1+}$ nickelate",
  "title_text": "Dichotomous electronic system in a bilayer Ni^1+ nickelate",
  "type": "preprint",
  "updated_at": "2026-10-30T12:35:50Z",
  "url": "https://research.draconitic.com/paper/c7cmpc6nvgtx3",
  "venue": "arXiv",
  "versions": []
}