{
  "id": "1507.03930",
  "version": "v1",
  "published": "2015-07-14T17:08:59.000Z",
  "updated": "2015-07-14T17:08:59.000Z",
  "title": "Ferromagnetic and underscreened Kondo behavior in quantum dot arrays",
  "authors": [
    "J. A. Andrade",
    "D. J. García",
    "Pablo S. Cornaglia"
  ],
  "comment": "9 pages, 7 figures",
  "categories": [
    "cond-mat.mes-hall",
    "cond-mat.str-el"
  ],
  "abstract": "We analyze the low energy properties of a device with $N+1$ quantum dots in a star configuration. A central quantum dot is tunnel coupled to source and drain electrodes and to $N$ quantum dots. Extending results by Baruselli et al. [Phys. Rev. Lett. 111 047201 (2013)] we show that, in the appropriate parameter regime, the low energy Hamiltonian of the system is a ferromagnetic Kondo model for a $S=(N-1)/2$ impurity spin. For small enough interdot tunnel coupling, however, a two-stage Kondo effect takes place as the temperature is decreased. The spin $1/2$ in the central quantum dot is Kondo screened first and at lower temperatures the antiferromagnetic coupling to the side-coupled quantum dots leads to an underscreened $S=N/2$ Kondo effect. We present numerical results for the thermodynamic and spectral properties of the system which show a singular behavior at low temperatures and allow to characterize the different strongly correlated regimes of the device.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2015-07-14T17:08:59.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "quantum dot arrays",
      "underscreened kondo behavior",
      "central quantum dot",
      "ferromagnetic kondo model",
      "two-stage kondo effect"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 9,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}