{
  "id": "0909.2477",
  "version": "v2",
  "published": "2009-09-14T06:39:41.000Z",
  "updated": "2009-09-14T22:02:27.000Z",
  "title": "Collective modes of a helical liquid",
  "authors": [
    "S. Raghu",
    "Suk Bum Chung",
    "Xiao-Liang Qi",
    "Shou-Cheng Zhang"
  ],
  "comment": "4 Pages, 2 Figures",
  "journal": "Phys. Rev. Lett. 104, 116401 (2010)",
  "doi": "10.1103/PhysRevLett.104.116401",
  "categories": [
    "cond-mat.mes-hall"
  ],
  "abstract": "We study low energy collective modes and transport properties of the \"helical metal\" on the surface of a topological insulator. At low energies, electrical transport and spin dynamics at the surface are exactly related by an operator identity equating the electric current to the in-plane components of the spin degrees of freedom. From this relation it follows that an undamped spin wave always accompanies the sound mode in the helical metal -- thus it is possible to `hear' the sound of spins. In the presence of long range Coulomb interactions, the surface plasmon mode is also coupled to the spin wave, giving rise to a hybridized \"spin-plasmon\" mode. We make quantitative predictions for the spin-plasmon in ${\\rm Bi}_2{\\rm Se}_3$, and discuss its detection in a spin-grating experiment.",
  "revisions": [
    {
      "version": "v2",
      "updated": "2009-09-14T22:02:27.000Z"
    }
  ],
  "analyses": {
    "subjects": [
      "71.10.Ay",
      "71.45.Gm",
      "72.15.Nj"
    ],
    "keywords": [
      "helical liquid",
      "long range coulomb interactions",
      "study low energy collective modes",
      "spin wave",
      "surface plasmon mode"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "publisher": "APS",
      "journal": "Physical Review Letters",
      "year": 2010,
      "month": "Mar",
      "volume": 104,
      "number": 11,
      "pages": 116401
    },
    "note": {
      "typesetting": "TeX",
      "pages": 4,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "adsabs": "2010PhRvL.104k6401R"
    }
  }
}