{
  "abstract": "Phononic frequency combs are equidistant spectral ladders generated when a driven vibrational mode transfers energy to an autoparametrically excited subharmonic mode through anharmonic intermode coupling. In previous studies, the coupling strength governing this energy transfer has typically been treated as a free parameter, extracted from a fabricated device, or adopted from an earlier calculation for a specific mode pair. As a result, whether a given crystal can support a phononic frequency comb, and the drive strength required to generate it, has not been predictable a priori. Here we obtain the complete parameter set from density functional theory. Twisted bilayers of \\MoSSe{} and \\MoSMoSe{} at the commensurate angle $21.787^{\\circ}$ adopt space group $P3$ in a 42-atom \\rootseven{} moiré supercell. The second-order force constants provide the mode frequencies; the third-order constants provide the linewidths through the Boltzmann transport equation and hence the quality factors; and the same third-order tensor projected onto the phonon eigenvectors of a chosen mode pair provides the anharmonic couplings $\\kt$ and $\\kss$. Both bilayers constitute a mode pair within $0.8\\%$ of the $2\\!:\\!1$ resonance with $ω_1/ω_2 = 1.9923$ in \\MoSSe{} and $1.9943$ in \\MoSMoSe{}. By integrating the resulting two-mode equations, both modes generate combs through a discontinuous transition: at $701\\,\\fth$ in \\MoSSe{} the envelope variance rises from $2.1\\times10^{3}$ to $1.37\\times10^{4}$ and the tooth count of mode 1 from 7 to 16 within a single $5\\,\\fth$ increment, identifying the onset as subcritical. The spectral entropy peaks \\emph{before} this jump, at $341\\,\\fth$. The two compounds carry comparable coupling, differing by a factor of $1.2$. However, the comb excitation threshold is set by the quality-factors of signal modes: $Q_2 = 672$ for \\MoSSe{} and $Q_2 = 3844$ for \\MoSMoSe{}.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.13825",
  "author_total": 2,
  "authors": [
    {
      "name": "Naman Arora"
    },
    {
      "name": "Adarsh Ganesan"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/f4qxt24gc4dta.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.13825",
  "fulltext_url": null,
  "id": "f4qxt24gc4dta",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.13825",
  "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"
    ],
    [
      "arxiv",
      "nlin.PS"
    ],
    [
      "openalex",
      "2505|2D Materials and Applications"
    ]
  ],
  "openalex": "W7221556806",
  "pdf_url": "https://arxiv.org/pdf/2610.13825",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-09",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/f4qxt24gc4dta.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:28:36Z",
      "native_id": "2610.13825",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.13825"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:cond-mat.mtrl-sci",
      "subfield": "condensed-matter"
    },
    {
      "field": "physics",
      "origin": "arxiv:nlin.PS",
      "subfield": "statistical-nonlinear"
    }
  ],
  "title": "Phononic Frequency Combs in Twisted Bilayer Transition Metal Dichalcogenide Heterostructures from First Principles",
  "title_text": "Phononic Frequency Combs in Twisted Bilayer Transition Metal Dichalcogenide Heterostructures from First Principles",
  "type": "preprint",
  "updated_at": "2026-10-30T12:28:36Z",
  "url": "https://research.draconitic.com/paper/f4qxt24gc4dta",
  "venue": "arXiv",
  "versions": []
}