{
  "abstract": "Electronic flat bands associated with quenched kinetic energy and heavy electron mass have attracted great interest for promoting strong electronic correlations and emergent phenomena such as high-temperature charge fractionalization and superconductivity. Intense experimental and theoretical research has been devoted to establishing the rich non-trivial metallic and heavy fermion phases intertwined with such localized electronic states. Here, we investigate the transition metal oxide spinel LiV2O4, an enigmatic heavy fermion compound lacking localized f orbital states. We use angle-resolved photoemission spectroscopy and dynamical mean field theory to reveal a new kind of correlation-induced flat band with suppressed inter-atomic electron hopping arising from intra-atomic Hund coupling. The appearance of heavy quasiparticles is ascribed to a proximate orbital-selective Mott state characterized by fluctuating local moments as evidenced by complementary magnetotransport measurements. The spectroscopic fingerprints of long-lived quasiparticles and their disappearance with increasing temperature further support the emergence of a high-temperature bad metal state observed in transport data. This work resolves a long-standing puzzle on the origin of heavy fermion behavior and unconventional transport in LiV2O4. Simultaneously, it opens a new path to achieving flat bands through electronic interactions in d-orbital systems with geometrical frustration, potentially enabling the realization of exotic phases of matter such as the fractionalized Fermi liquids.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2502.07234",
  "author_total": 29,
  "authors": [
    {
      "name": "Dongjin Oh"
    },
    {
      "name": "Alexander Hampel"
    },
    {
      "name": "Joshua P Wakefield"
    },
    {
      "name": "Peter Moen"
    },
    {
      "name": "Steef Smit"
    },
    {
      "name": "Xiangyu Luo"
    },
    {
      "name": "Marta Zonno"
    },
    {
      "name": "Sergey Gorovikov"
    },
    {
      "name": "Mats Leandersson"
    },
    {
      "name": "Craig Polley"
    },
    {
      "name": "Asish K Kundu"
    },
    {
      "name": "Anil Rajapitamahuni"
    },
    {
      "name": "Elio Vescovo"
    },
    {
      "name": "Chris Jozwiak"
    },
    {
      "name": "Aaron Bostwick"
    },
    {
      "name": "Eli Rotenberg"
    },
    {
      "name": "Masahiko Isobe"
    },
    {
      "name": "Manish Verma"
    },
    {
      "name": "Matteo Crispino"
    },
    {
      "name": "Martin Grundner"
    },
    {
      "name": "Fabian B Kugler"
    },
    {
      "name": "Olivier Parcollet"
    },
    {
      "name": "Ulrich Schollwöck"
    },
    {
      "name": "Hidenori Takagi"
    },
    {
      "name": "Andrea Damascelli"
    },
    {
      "name": "Giorgio Sangiovanni"
    },
    {
      "name": "Joseph G Checkelsky"
    },
    {
      "name": "Antoine Georges"
    },
    {
      "name": "Riccardo Comin"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/48qxz8adhy5md.bib",
  "cited_by": 4,
  "doi": "10.1073/pnas.2518213122",
  "fulltext_url": null,
  "id": "48qxz8adhy5md",
  "issns": [
    "0027-8424",
    "1091-6490"
  ],
  "landing_url": "https://hal.science/hal-05507548v1",
  "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": [
    [
      "hal",
      "0.phys"
    ],
    [
      "openalex",
      "3104|Advanced Condensed Matter Physics"
    ]
  ],
  "openalex": "W4415965216",
  "pdf_url": "https://hal.science/hal-05507548/document",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-14",
  "publisher": "National Academy of Sciences",
  "ris": "https://research.draconitic.com/paper/48qxz8adhy5md.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:21Z",
      "native_id": "hal-05507548",
      "source": "hal",
      "url": "https://hal.science/hal-05507548v1"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "openalex:3104|Advanced Condensed Matter Physics",
      "subfield": "condensed-matter"
    }
  ],
  "title": "Hund flat band in a frustrated spinel oxide",
  "title_text": "Hund flat band in a frustrated spinel oxide",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:17:21Z",
  "url": "https://research.draconitic.com/paper/48qxz8adhy5md",
  "venue": "Proceedings of the National Academy of Sciences of the United States of America",
  "versions": []
}