{
  "abstract": "The exceptionally high thermal conductivity of cubic boron arsenide (BAs) arises from suppressed three-phonon scattering associated with its large acoustic--optical gap. In this regime, four-phonon processes become non-negligible, creating an unusual scattering hierarchy with unexplored consequences for nonequilibrium phonon dynamics. Here, time-resolved x-ray diffuse scattering reveals exceptionally slow, branch-dependent acoustic phonon thermalization and long-lived coherence. Exploiting branch sensitivity in one-phonon diffuse scattering, we resolve transverse acoustic (TA) and longitudinal acoustic (LA) thermalization times of 29.2 and 13.9~ps, respectively; even the LA timescale is at least three times that in common semiconductors. Phonon dispersion calculations assign coherent oscillations at 0.19 and 0.27~THz to the TA and LA modes, respectively; both persist with little decay over 50~ps, with comparable coherence found only in diamond. These findings provide a direct dynamical manifestation of the weak phonon scattering underlying the exceptional thermal transport of BAs.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.13541",
  "author_total": 14,
  "authors": [
    {
      "name": "Zeyu Xiang"
    },
    {
      "name": "Ying Peng"
    },
    {
      "name": "Ange Benise Niyikiza"
    },
    {
      "name": "Fanghao Zhang"
    },
    {
      "name": "Haoyuan Li"
    },
    {
      "name": "Takahiro Sato"
    },
    {
      "name": "Thomas Linker"
    },
    {
      "name": "Yanwen Sun"
    },
    {
      "name": "Meredith Henstridge"
    },
    {
      "name": "Vincent Esposito"
    },
    {
      "name": "James F. Cotter"
    },
    {
      "name": "Diling Zhu"
    },
    {
      "name": "Zhifeng Ren"
    },
    {
      "name": "Bolin Liao"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/cppbs1ara32xt.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.13541",
  "fulltext_url": null,
  "id": "cppbs1ara32xt",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.13541",
  "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",
      "2505|Thermal properties of materials"
    ]
  ],
  "openalex": "W7213311716",
  "pdf_url": "https://arxiv.org/pdf/2609.13541",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-11",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/cppbs1ara32xt.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:21:25Z",
      "native_id": "2609.13541",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.13541"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:cond-mat.mtrl-sci",
      "subfield": "condensed-matter"
    }
  ],
  "title": "Slow Thermalization and Long-Lived Coherence across Acoustic Phonon Branches in BAs",
  "title_text": "Slow Thermalization and Long-Lived Coherence across Acoustic Phonon Branches in BAs",
  "type": "preprint",
  "updated_at": "2026-10-30T12:21:25Z",
  "url": "https://research.draconitic.com/paper/cppbs1ara32xt",
  "venue": "arXiv",
  "versions": []
}