{
  "id": "2302.04984",
  "version": "v1",
  "published": "2023-02-10T00:08:00.000Z",
  "updated": "2023-02-10T00:08:00.000Z",
  "title": "Ultrafast electron-electron scattering in metallic phase of 2H-NbSe$_2$ probed by high harmonic generation",
  "authors": [
    "K. S. Shimomura",
    "K. Uchida",
    "N. Nagai",
    "S. Kusaba",
    "K. Tanaka"
  ],
  "categories": [
    "cond-mat.mes-hall",
    "physics.optics"
  ],
  "abstract": "Electron-electron scattering on the order of a few to tens of femtoseconds plays a crucial role in the ultrafast electron dynamics of conventional metals. When mid-infrared light is used for driving and the period of light field is comparable to the scattering time in metals, unique light-driven states and nonlinear optical responses associated with the scattering process are expected to occur. Here, we use high-harmonics spectroscopy to investigate the effect of electron-electron scattering on the electron dynamics in thin film 2H-NbSe$_2$ driven by a mid-infrared field. We observed odd-order high harmonics up to 9th order as well as a broadband emission from hot electrons in the energy range from 1.5 to 4.0 eV. The electron-electron scattering time in NbSe$_2$ was estimated from the broadband emission to be almost the same as the period of the mid-infrared light field. A comparison between experimental results and a numerical calculation reveals that a kind of resonance between scattering and driving enhances the non-perturbative behavior of high harmonics in metals, causing a highly non-equilibrium electronic state corresponding to several thousand Kelvin.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2023-02-10T00:08:00.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "high harmonic generation",
      "ultrafast electron-electron scattering",
      "metallic phase",
      "non-equilibrium electronic state corresponding",
      "light field"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}