{
  "id": "2407.21557",
  "version": "v1",
  "published": "2024-07-31T12:26:35.000Z",
  "updated": "2024-07-31T12:26:35.000Z",
  "title": "Andreev Reflection in the Quantum Hall Regime at an Al/InAs Junction on a Cleaved Edge",
  "authors": [
    "Takafumi Akiho",
    "Hiroshi Irie",
    "Yusuke Nakazawa",
    "Satoshi Sasaki",
    "Norio Kumada",
    "Koji Muraki"
  ],
  "comment": "7 pages, 4 figures",
  "categories": [
    "cond-mat.mes-hall"
  ],
  "abstract": "We have fabricated a superconductor/semiconductor junction composed of Al and InAs using cleaved edge overgrowth (CEO). By exploiting the unique geometry with a thin Al/Pt/Al trilayer formed on the side surface of an in-situ cleaved heterostructure wafer containing an InAs quantum well (QW), we achieve a superconducting critical field of $\\sim 5$~T, allowing superconductivity and quantum Hall (QH) effects to coexist down to filling factor $\\nu = 3$. Andreev reflection at zero magnetic field shows a conductance enhancement that is limited solely by the Fermi velocity mismatch, demonstrating a virtually barrier-free, high-quality S/Sm junction. Bias spectroscopy in the QH regime reveals a clear bias dependence indicating the superconducting gap, with the reduced downstream resistance demonstrating that the electron-hole Andreev conversion probability consistently exceeds 50\\%. Our results, obtained in a new experimental regime characterized by a clean edge-contacted junction, a much smaller superconducting gap, and a narrow superconducting electrode less than the coherence length, open a new avenue for both theoretical and experimental studies of the interplay between superconductivity and QH effects and the engineering of exotic quasiparticles.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2024-07-31T12:26:35.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "quantum hall regime",
      "andreev reflection",
      "cleaved edge",
      "al/inas junction",
      "cleaved heterostructure wafer containing"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 7,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}