{
  "abstract": "Lead-barium niobate Pb$_{1-x}$Ba$_x$Nb$_2$O$_6$ is a tetragonal tungsten-bronze ferroelectric that exhibits enhanced functional properties near a morphotropic phase boundary separating orthorhombic and tetragonal phases. Using first-principles electronic-structure calculations combined with ab initio molecular dynamics, we investigate how Ba substitution modifies cation-site occupancy, local distortions, and polarization behavior across the solid solution. By explicitly accounting for vacancy ordering and the inequivalent $A$-site cages intrinsic to the tungsten-bronze framework, we identify the structural origin of the orthorhombic-to-tetragonal transition. Increasing Ba content progressively weakens the cooperative in-plane off-centering of Pb ions in the pentagonal channels and promotes out-of-plane displacements of Nb and $A$-site cations, leading to a rotation of the spontaneous polarization from [110] to [001]. The transition occurs near $x \\approx 0.6$, in quantitative agreement with experimental phase diagrams. These results provide a microscopic interpretation of the morphotropic phase boundary in Pb$_{1-x}$Ba$_x$Nb$_2$O$_6$ and establish a clear structure-polarization relationship for tungsten-bronze ferroelectrics.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.41601",
  "author_total": 2,
  "authors": [
    {
      "name": "Marco Fornari"
    },
    {
      "name": "Virginia Carnevali"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/6qpkbcv67anje.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.41601",
  "fulltext_url": null,
  "id": "6qpkbcv67anje",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.41601",
  "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/2610.41601",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-30",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/6qpkbcv67anje.ris",
  "sources": [
    {
      "first_seen": "2026-11-02T12:21:15Z",
      "native_id": "2610.41601",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.41601"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:cond-mat.mtrl-sci",
      "subfield": "condensed-matter"
    }
  ],
  "title": "Microscopic structure at the morphotropic phase boundary in lead-barium meta-niobat",
  "title_text": "Microscopic structure at the morphotropic phase boundary in lead-barium meta-niobat",
  "type": "preprint",
  "updated_at": "2026-11-04T15:20:51Z",
  "url": "https://research.draconitic.com/paper/6qpkbcv67anje",
  "venue": "arXiv",
  "versions": []
}