{
  "id": "1412.5835",
  "version": "v1",
  "published": "2014-12-18T12:28:12.000Z",
  "updated": "2014-12-18T12:28:12.000Z",
  "title": "On the universal absorption of two-dimensional systems",
  "authors": [
    "T. Stauber",
    "D. Noriega-Perez",
    "J. Schliemann"
  ],
  "comment": "7 pages",
  "categories": [
    "cond-mat.mes-hall"
  ],
  "abstract": "We discuss the optical conductivity of several non-interacting two-dimensional (2D) semiconducting systems focusing on gapped Dirac and Schr\\\"odinger fermions as well as on a system mixing these two types. Close to the band-gap, we can define a universal optical conductivity quantum of $\\sigma_0=\\frac{1}{16}\\frac{e^2}{\\hbar}$ for the pure systems. The effective optical conductivity then depends on the degeneracy factors $g_s$ (spin) and $g_v$ (valley) and on the curvature around the band-gap $\\nu$, i.e., it generally reads $\\sigma=g_sg_v\\nu\\sigma_0$. For a system composed of both types of carriers, the optical conductivity becomes non-universal.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2014-12-18T12:28:12.000Z"
    }
  ],
  "analyses": {
    "subjects": [
      "78.67.-n",
      "78.68.+m",
      "73.20.-r",
      "78.90.+t"
    ],
    "keywords": [
      "two-dimensional systems",
      "universal absorption",
      "universal optical conductivity quantum",
      "degeneracy factors",
      "pure systems"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "doi": "10.1103/PhysRevB.91.115407",
      "journal": "Physical Review B",
      "year": 2015,
      "month": "Mar",
      "volume": 91,
      "number": 11,
      "pages": 115407
    },
    "note": {
      "typesetting": "TeX",
      "pages": 7,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "adsabs": "2015PhRvB..91k5407S"
    }
  }
}