{
  "abstract": "The transconductance $g_m = dI_D/dV_G$ of a field-effect transistor (FET) is conventionally read as a proxy for carrier density. We show that it is instead a spectroscopic probe of the carrier distribution: because $g_m$ weights the spectral current $j(E)$ by the gate-voltage derivative $\\partial f(E)/\\partial V_G$ and integrates over energy, it is sensitive to the \\emph{shape} of $f(E)$, not merely its integrated weight $n$. We develop an energy-resolved transport framework for two-dimensional (2D) FETs and, within a gate-independent spectral-kernel approximation, derive the decomposition $g_m = g_m^{(n)} + g_m^{(α)}$ into the conventional density-modulation term $g_m^{(n)}$ and a distribution-shape-driven term $g_m^{(α)}$. The latter, obtained as the residual after subtracting the smooth density-modulation background from the measured $g_m$, exhibits a characteristic anomalous peak at a gate voltage $V_G^{\\rm pk}$. This peak has no counterpart in equilibrium transport and \\emph{cannot be explained by carrier density modulation alone}. With the spectral kernel calibrated, the peak position and height -- extracted from standard DC/lock-in $g_m$ sweeps -- constrain the hot-carrier energy $E_0$, spectral width $σ$, and generation threshold $n_c$, realizing a steady-state, all-electrical spectroscopy of the carrier distribution. An optional time-resolved extension further recovers the carrier relaxation time $τ$ from the transient response following a pump excitation, establishing the 2D FET as a distribution-function spectrometer that requires no optical readout.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": "Journal reference: Phys. Rev. Applied 26, 034075 (2026)",
  "arxiv": "2607.15578",
  "author_total": 1,
  "authors": [
    {
      "name": "Katsunori Wakabayashi"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/56c3wp1sdbp76.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2607.15578",
  "fulltext_url": null,
  "id": "56c3wp1sdbp76",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2607.15578",
  "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.mes-hall"
    ],
    [
      "arxiv",
      "cond-mat.mtrl-sci"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2607.15578",
  "pmcid": null,
  "pmid": null,
  "published": "2026-08-20",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/56c3wp1sdbp76.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:26:03Z",
      "native_id": "2607.15578",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2607.15578"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:cond-mat.mes-hall",
      "subfield": "condensed-matter"
    }
  ],
  "title": "Hot-Carrier Distribution Spectroscopy by Transconductance in Two-Dimensional Field-Effect Transistors",
  "title_text": "Hot-Carrier Distribution Spectroscopy by Transconductance in Two-Dimensional Field-Effect Transistors",
  "type": "preprint",
  "updated_at": "2026-10-30T12:26:03Z",
  "url": "https://research.draconitic.com/paper/56c3wp1sdbp76",
  "venue": "arXiv",
  "versions": [
    {
      "doi": "10.1103/fm13-kghl",
      "pid": null,
      "relation": "published-as",
      "title": null,
      "venue": null
    }
  ]
}