{
  "id": "1102.4512",
  "version": "v4",
  "published": "2011-02-22T14:09:30.000Z",
  "updated": "2011-08-21T11:04:09.000Z",
  "title": "Weak antilocalization in HgTe quantum wells and topological surface states: Massive versus massless Dirac fermions",
  "authors": [
    "G. Tkachov",
    "E. M. Hankiewicz"
  ],
  "comment": "14 pages, 10 figures, version as published",
  "journal": "Phys. Rev. B 84, 035444 (2011)",
  "doi": "10.1103/PhysRevB.84.035444",
  "categories": [
    "cond-mat.mes-hall"
  ],
  "abstract": "HgTe quantum wells and surfaces of three-dimensional topological insulators support Dirac fermions with a single-valley band dispersion. In the presence of disorder they experience weak antilocalization, which has been observed in recent transport experiments. In this work we conduct a comparative theoretical study of the weak antilocalization in HgTe quantum wells and topological surface states. The difference between these two single-valley systems comes from a finite band gap (effective Dirac mass) in HgTe quantum wells in contrast to gapless (massless) surface states in topological insulators. The finite effective Dirac mass implies a broken internal symmetry, leading to suppression of the weak antilocalization in HgTe quantum wells at times larger than certain t_M, inversely proportional to the Dirac mass. This corresponds to the opening of a relaxation gap 1/t_M in the Cooperon diffusion mode which we obtain from the Bethe-Salpeter equation including relevant spin degrees of freedom. We demonstrate that the relaxation gap exhibits an interesting nonmonotonic dependence on both carrier density and band gap, vanishing at a certain combination of these parameters. The weak-antilocalization conductivity reflects this nonmonotonic behavior which is unique to HgTe QWs and absent for topological surface states. On the other hand, the topological surface states exhibit specific weak-antilocalization magnetoconductivity in a parallel magnetic field due to their exponential decay in the bulk.",
  "revisions": [
    {
      "version": "v4",
      "updated": "2011-08-21T11:04:09.000Z"
    }
  ],
  "analyses": {
    "subjects": [
      "73.63.Hs",
      "85.75.-d",
      "73.20.Fz"
    ],
    "keywords": [
      "hgte quantum wells",
      "topological surface states",
      "weak antilocalization",
      "massless dirac fermions",
      "effective dirac mass"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "publisher": "APS",
      "journal": "Physical Review B",
      "year": 2011,
      "month": "Jul",
      "volume": 84,
      "number": 3,
      "pages": "035444"
    },
    "note": {
      "typesetting": "TeX",
      "pages": 14,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "adsabs": "2011PhRvB..84c5444T"
    }
  }
}