{
  "abstract": "Understanding and controlling the optical, thermal and mechanical properties of K$_2$PtCl$_6$-type double perovskites is essential for the design of lead-free, high-performance thermoelectric and optoelectronic materials. In this study, we investigate Cs$_2$SnI$_6$ using temperature-dependent near-resonance Raman scattering, complemented by density functional theory-based phonon calculations. The appearance of Raman-forbidden phonon modes in the Raman response at cryogenic temperatures provides strong evidence for local symmetry breaking that does not develop into a global structural phase transition. Through detailed analysis of phonon intensities, energies, and spectral lineshapes, we characterize the temperature evolution of the symmetry-broken structural response of Cs$_2$SnI$_6$. Below 200 K, multi-phonon scattering is strongly enhanced, and symmetry-forbidden Raman modes emerge. The temperature dependence of phonon intensities follows a phenomenological Arrhenius behavior, revealing an activation energy of 15-20 meV. These results establish temperature-dependent Raman spectroscopy as a sensitive probe of local structural distortions and anharmonic structural dynamics in Cs$_2$SnI$_6$, providing a robust experimental basis for discussing the microscopic origins of symmetry breaking and electron-phonon coupling in halide double perovskites.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2611.01830",
  "author_total": 10,
  "authors": [
    {
      "name": "Tomke E. Glier"
    },
    {
      "name": "Nicholas J. Weadock"
    },
    {
      "name": "Julian A. Vigil"
    },
    {
      "name": "Cole Shank"
    },
    {
      "name": "Xixi Qin"
    },
    {
      "name": "Gabriel J. Graf"
    },
    {
      "name": "Hemamala I. Karunadasa"
    },
    {
      "name": "Volker Blum"
    },
    {
      "name": "Michael F. Toney"
    },
    {
      "name": "Dmitry Reznik"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/667mt9kfmzfa8.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2611.01830",
  "fulltext_url": null,
  "id": "667mt9kfmzfa8",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2611.01830",
  "language": null,
  "licence": "LicenseRef-arXiv-nonexclusive-1.0",
  "licence_label": "arXiv licence",
  "licence_source": "article",
  "licence_url": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "cond-mat.mtrl-sci"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2611.01830",
  "pmcid": null,
  "pmid": null,
  "published": "2026-11-01",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/667mt9kfmzfa8.ris",
  "sources": [
    {
      "first_seen": "2026-11-03T12:20:59Z",
      "native_id": "2611.01830",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2611.01830"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:cond-mat.mtrl-sci",
      "subfield": "condensed-matter"
    }
  ],
  "title": "Temperature-Dependent Raman Signatures of Local Symmetry Breaking in Vacancy Double Perovskite Cs$_2$SnI$_6$",
  "title_text": "Temperature-Dependent Raman Signatures of Local Symmetry Breaking in Vacancy Double Perovskite Cs_2SnI_6",
  "type": "preprint",
  "updated_at": "2026-11-05T15:20:18Z",
  "url": "https://research.draconitic.com/paper/667mt9kfmzfa8",
  "venue": "arXiv",
  "versions": [
    {
      "doi": "10.1016/j.newton.2026.100724",
      "pid": null,
      "relation": "published-as",
      "title": null,
      "venue": null
    }
  ]
}