{
  "id": "1307.4668",
  "version": "v1",
  "published": "2013-07-17T15:15:11.000Z",
  "updated": "2013-07-17T15:15:11.000Z",
  "title": "Non-monotonic spin relaxation and decoherence in graphene quantum dots with spin-orbit interactions",
  "authors": [
    "Marco O. Hachiya",
    "Guido Burkard",
    "J. Carlos Egues"
  ],
  "comment": "8 pages, 3 figures",
  "journal": "Phys. Rev. B 89, 115427 (2014)",
  "doi": "10.1103/PhysRevB.89.115427",
  "categories": [
    "cond-mat.mes-hall"
  ],
  "abstract": "We investigate the spin relaxation and decoherence in a single-electron graphene quantum dot with Rashba and intrinsic spin-orbit interactions. We derive an effective spin-phonon Hamiltonian via the Schrieffer-Wolff transformation in order to calculate the spin relaxation time T_1 and decoherence time T_2 within the framework of the Bloch-Redfield theory. In this model, the emergence of a non-monotonic dependence of T_1 on the external magnetic field is attributed to the Rashba spin-orbit coupling-induced anticrossing of opposite spin states. A rapid decrease of T_1 occurs when the spin and orbital relaxation rates become comparable in the vicinity of the spin-mixing energy-level anticrossing. By contrast, the intrinsic spin-orbit interaction leads to a monotonic magnetic field dependence of the spin relaxation rate which is caused solely by the direct spin-phonon coupling mechanism. Within our model, we demonstrate that the decoherence time T_2 ~ 2 T_1 is dominated by relaxation processes for the electron-phonon coupling mechanisms in graphene up to leading order in the spin-orbit interaction. Moreover, we show that the energy anticrossing also leads to a vanishing pure spin dephasing rate for these states for a super-Ohmic bath.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2013-07-17T15:15:11.000Z"
    }
  ],
  "analyses": {
    "subjects": [
      "03.67.Lx",
      "76.60.Es",
      "73.22.Pr"
    ],
    "keywords": [
      "graphene quantum dot",
      "non-monotonic spin relaxation",
      "pure spin dephasing rate",
      "intrinsic spin-orbit interaction",
      "relaxation rate"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "publisher": "APS",
      "journal": "Physical Review B",
      "year": 2014,
      "month": "Mar",
      "volume": 89,
      "number": 11,
      "pages": 115427
    },
    "note": {
      "typesetting": "TeX",
      "pages": 8,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "adsabs": "2014PhRvB..89k5427H"
    }
  }
}