{
  "abstract": "We establish a pressure-correlation phase diagram that yields multiple pressure-tunable quantum phase transitions in iron oxyhydroxide ($ε$-FeOOH) across three critical pressures, $P_{c1}>P_{c2}>P_{c3}$. The transitions arise from the competition among electron-correlation, crystal-field, and Hund's coupling. First-principles calculations reveal that the earlier reported high-spin (HS) to low-spin (LS) crossover at correlation-sensitive $P_{c1}$ is accompanied by a transition from charge-transfer to Mott insulating (CTI-MI) phase, and a change in the spin-quantization axis (SQA) from $\\hat{y}$ to $\\hat{x}$. The HS-LS crossover and CTI-MI transition is driven by the simultaneous increase in crystal-field splitting and decrease in Hund's coupling. The critical pressure $P_{c2}$ governing the structural transition from centrosymmetric $Pnnm$ phase to noncentrosymmetric $P2_1nm$ phase is found to be independent of electron-correlation. When correlation is strong, a third critical pressure ($P_{c3}$) emerges in the lower-pressure regime of the phase diagram. Validating the recent experimental observation, $P_{c3}$ is responsible for changing the SQA from $\\hat{z}$ to $\\hat{y}$. By exhibiting altermagnetism in both $P2_1nm$ and $Pnnm$ phases and possessing finite anomalous Hall conductivity (AHC) only for SQA along $\\hat{x}$ and $\\hat{y}$, $ε$-FeOOH enables a unique piezo-anomalous Hall effect where one can switch on the AHC at a lower pressure and change its direction at a higher pressure.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2611.03180",
  "author_total": 3,
  "authors": [
    {
      "name": "Arijit Mandal"
    },
    {
      "name": "Nayana Devaraj"
    },
    {
      "name": "Birabar Ranjit Kumar Nanda"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/3c7610rzv2fgk.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2611.03180",
  "fulltext_url": null,
  "id": "3c7610rzv2fgk",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2611.03180",
  "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"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2611.03180",
  "pmcid": null,
  "pmid": null,
  "published": "2026-11-02",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/3c7610rzv2fgk.ris",
  "sources": [
    {
      "first_seen": "2026-11-03T12:21:04Z",
      "native_id": "2611.03180",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2611.03180"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:cond-mat.mtrl-sci",
      "subfield": "condensed-matter"
    }
  ],
  "title": "Pressure-correlation phase diagram unraveling quantum phase transitions in altermagnetic $ε$-FeOOH and realization of piezo-anomalous Hall effect",
  "title_text": "Pressure-correlation phase diagram unraveling quantum phase transitions in altermagnetic ε-FeOOH and realization of piezo-anomalous Hall effect",
  "type": "preprint",
  "updated_at": "2026-11-05T15:20:21Z",
  "url": "https://research.draconitic.com/paper/3c7610rzv2fgk",
  "venue": "arXiv",
  "versions": []
}