{
  "id": "1306.5290",
  "version": "v2",
  "published": "2013-06-22T05:41:37.000Z",
  "updated": "2013-11-29T06:39:24.000Z",
  "title": "Phase Diagrams for the $ν$ = 1/2 Fractional Quantum Hall Effect in Electron Systems Confined to Symmetric, Wide GaAs Quantum Wells",
  "authors": [
    "J. Shabani",
    "Y. Liu",
    "M. Shayegan",
    "L. N. Pfeiffer",
    "K. W. West",
    "K. W. Baldwin"
  ],
  "comment": "Accepted for publication in Phys. Rev. B",
  "journal": "Phys. Rev. B 88, 245413 (2013)",
  "doi": "10.1103/PhysRevB.88.245413",
  "categories": [
    "cond-mat.mes-hall"
  ],
  "abstract": "We report an experimental investigation of fractional quantum Hall effect (FQHE) at the even-denominator Landau level filling factor $\\nu$ = 1/2 in very high quality wide GaAs quantum wells, and at very high magnetic fields up to 45 T. The quasi-two-dimensional electron systems we study are confined to GaAs quantum wells with widths $W$ ranging from 41 to 96 nm and have variable densities in the range of $\\simeq 4 \\times 10^{11}$ to $\\simeq 4 \\times 10^{10}$ cm$^{-2}$. We present several experimental phase diagrams for the stability of the $\\nu=1/2$ FQHE in these quantum wells. In general, for a given $W$, the 1/2 FQHE is stable in a limited range of intermediate densities where it has a bilayer-like charge distribution; it makes a transition to a compressible phase at low densities and to an insulating phase at high densities. The densities at which the $\\nu=1/2$ FQHE is stable are larger for narrower quantum wells. Moreover, even a slight charge distribution asymmetry destabilizes the $\\nu=1/2$ FQHE and turns the electron system into a compressible state. We also present a plot of the symmetric-to-antisymmetric subband separation ($\\Delta_{SAS}$), which characterizes the inter-layer tunneling, vs density for various $W$. This plot reveals that $\\Delta_{SAS}$ at the boundary between the compressible and FQHE phases increases \\textit{linearly} with density for all the samples. Finally, we summarize the experimental data in a diagram that takes into account the relative strengths of the inter-layer and intra-layer Coulomb interactions and $\\Delta_{SAS}$. We conclude that, consistent with the conclusions of some of the previous studies, the $\\nu=1/2$ FQHE observed in wide GaAs quantum wells with symmetric charge distribution is stabilized by a delicate balance between the inter-layer and intra-layer interactions, and is very likely described by a two-component ($\\Psi_{311}$) state.",
  "revisions": [
    {
      "version": "v2",
      "updated": "2013-11-29T06:39:24.000Z"
    }
  ],
  "analyses": {
    "subjects": [
      "73.21.Fg",
      "73.43.Qt"
    ],
    "keywords": [
      "wide gaas quantum wells",
      "fractional quantum hall effect",
      "phase diagrams",
      "electron systems",
      "charge distribution asymmetry destabilizes"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "publisher": "APS",
      "journal": "Physical Review B",
      "year": 2013,
      "month": "Dec",
      "volume": 88,
      "number": 24,
      "pages": 245413
    },
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "adsabs": "2013PhRvB..88x5413S"
    }
  }
}