{
  "id": "1407.7018",
  "version": "v2",
  "published": "2014-07-25T19:52:30.000Z",
  "updated": "2015-03-11T19:46:54.000Z",
  "title": "Scanning Gate Microscopy of Quantum Contacts Under Parallel Magnetic Field: Beating Patterns Between Spin-Split Transmission Peaks or Channel Openings",
  "authors": [
    "Andrii Kleshchonok",
    "Geneviève Fleury",
    "Jean-Louis Pichard",
    "Gabriel Lemarié"
  ],
  "comment": "11 pages, 17 figures",
  "journal": "Physical Review B (PRB), 2015, 91, pp.125416",
  "categories": [
    "cond-mat.mes-hall"
  ],
  "abstract": "We study the conductance $g$ of an electron interferometer created in a two dimensional electron gas between a nanostructured contact and the depletion region induced by the charged tip of a scanning gate microscope. Using non-interacting models, we study the beating pattern of interference fringes exhibited by the images giving $g$ as a function of the tip position when a parallel magnetic field is applied. The analytical solution of a simplified model allows us to distinguish between two cases: (i) If the field is applied everywhere, the beating of Fabry-P\\'erot oscillations of opposite spins gives rise to interference rings which can be observed at low temperatures when the contact is open between spin-split transmission resonances. (ii) If the field acts only upon the contact, the interference rings cannot be observed at low temperatures, but only at temperatures of the order of the Zeeman energy. For a contact made of two sites in series, a model often used for describing an inversion-symmetric double-dot setup, a pseudo-spin degeneracy is broken by the inter-dot coupling and a similar beating effect can be observed without magnetic field at temperatures of the order of the interdot coupling. Eventually, numerical studies of a quantum point contact with quantized conductance plateaus confirm that a parallel magnetic field applied everywhere or only upon the contact gives rises to similar beating effects between spin-split channel openings.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2014-07-25T19:52:30.000Z",
      "title": "Scanning Gate Microscopy of Quantum Contacts Opened Between Transmission Resonances",
      "abstract": "We study the conductance $g$ of an electron interferometer formed in a two dimensional electron gas between the charged tip of a scanning gate microscope and a nanostructured quantum contact. If the contact transmission exhibits successive resonances, we show that the images giving $g$ as a function of the tip position can exhibit novel interference rings in addition to Fabry-P\\'erot interference fringes spaced by half the Fermi wavelength. This is due to a beating effect between the contribution of two successive transmission peaks to $g$ and can be observed when the contact is opened between the peaks at a temperature of the order of the inter-peak energy spacing. We analytically study two contacts exhibiting the required double-peak structure: (i) The first one is made of a single quantum impurity with a parallel magnetic field, the spin degenerate Breit-Wigner resonance of its transmission being split by Zeeman effect; (ii) The second one is made of an inversion-symmetric double dot setup, where the pseudo-spin degeneracy is broken by the inter-dot coupling. Numerical studies of a quantum point contact with quantized conductance plateaus confirm that similar beating phenomena can be seen near a spin-split channel opening, when a parallel magnetic field is applied.",
      "comment": "12 pages, 20 figures",
      "journal": null,
      "doi": null
    },
    {
      "version": "v2",
      "updated": "2015-03-11T19:46:54.000Z"
    }
  ],
  "analyses": {
    "subjects": [
      "07.79.-v",
      "72.10.-d",
      "73.63.Rt"
    ],
    "keywords": [
      "scanning gate microscopy",
      "quantum contacts",
      "transmission resonances",
      "parallel magnetic field",
      "spin degenerate breit-wigner resonance"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "publisher": "APS",
      "journal": "Physical Review B",
      "doi": "10.1103/PhysRevB.91.125416",
      "year": 2015,
      "month": "Mar",
      "volume": 91,
      "number": 12,
      "pages": 125416
    },
    "note": {
      "typesetting": "TeX",
      "pages": 11,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "adsabs": "2015PhRvB..91l5416K"
    }
  }
}