{
  "abstract": "With the rapid development of integrated electro-optic and nonlinear optical devices based on lithium niobate (LiNbO$_3$, LN), thermal management is becoming a critical area of focus. However, experimental measurement of thermal transport in stoichiometric LiNbO$_3$ (sLN) remains scarce, and the intrinsic microscopic mechanisms remain to be established. Here, we combine the laser pump-probe technique of frequency-domain thermoreflectance (FDTR) with state-of-the-art machine-learned atomistic simulations to comprehensively investigate thermal transport in sLN. The measured and simulated room-temperature thermal conductivity ($κ$) values of sLN agree well, which are orders-of-magnitude lower than that of many classic and emerging semiconductors such as silicon. Furthermore, the temperature-dependent $κ$ exhibits a $T^{-α}$ scaling with $α$ near unity, suggesting that thermal transport is dominated by intrinsic phonon-phonon scattering. By comparing sLN with cubic boron arsenide (cBAs) which serves as an ultrahigh-$κ$ benchmark, we reveal that harmonic properties are not responsible for the low $κ$ of sLN, which feature phonon heat capacity and group velocities that are either higher than or comparable to those in cBAs. Instead, the low $κ$ originates from substantially stronger anharmonicity and larger scattering phase space. These two factors collectively suppress phonon lifetimes by 1-2 orders of magnitude, leading to a maximum phonon mean free path of approximately 140 nm. As a result, notable size effects emerge in thin-film sLN below 1 $μ$m, with $κ$ dropping to half the bulk value at 10 nm. Altogether, our findings establish a fundamental understanding of thermal transport in sLN and provide atomistic insights for thermal management in advanced lithium niobate technologies.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": "Journal reference: Phys. Rev. Materials 10, 094607, 2026",
  "arxiv": "2607.01673",
  "author_total": 7,
  "authors": [
    {
      "name": "Wenjiang Zhou"
    },
    {
      "name": "Fuwei Yang"
    },
    {
      "name": "Yuxi Wang"
    },
    {
      "name": "Weiheng Li"
    },
    {
      "name": "Wujuan Yan"
    },
    {
      "name": "Kexin Zhang"
    },
    {
      "name": "Bai Song"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/c17ppv2f75ng1.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2607.01673",
  "fulltext_url": null,
  "id": "c17ppv2f75ng1",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2607.01673",
  "language": null,
  "licence": "CC-BY-NC-ND-4.0",
  "licence_label": "CC BY-NC-ND 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by-nc-nd/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "cond-mat.mtrl-sci"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2607.01673",
  "pmcid": null,
  "pmid": null,
  "published": "2026-07-02",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/c17ppv2f75ng1.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:22:01Z",
      "native_id": "2607.01673",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2607.01673"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:cond-mat.mtrl-sci",
      "subfield": "condensed-matter"
    }
  ],
  "title": "Intrinsically low thermal conductivity of stoichiometric lithium niobate:Experimental measurement and microscopic origin",
  "title_text": "Intrinsically low thermal conductivity of stoichiometric lithium niobate:Experimental measurement and microscopic origin",
  "type": "preprint",
  "updated_at": "2026-10-30T12:22:01Z",
  "url": "https://research.draconitic.com/paper/c17ppv2f75ng1",
  "venue": "arXiv",
  "versions": [
    {
      "doi": "10.1103/ww2h-mrg7",
      "pid": null,
      "relation": "published-as",
      "title": null,
      "venue": null
    }
  ]
}