Probing Andreev edge state with shot noise

ORAL

Abstract

The existence of Andreev edge states (AESs) is one of the prerequisites to realize emergent excitations like Majorana fermion at the interface of normal or anomalous quantum Hall (QH) insulators and superconductor (SC). At a QH-SC interface the hybridized electron-hole states called AESs carry the current in the zero bias limit, whereas normal quasiparticles carry the current when the bias energy is higher than the superconducting gap. Here, we report on measurements of both electrical conductance and shot noise in a graphene QH and SC junction at integer filling ν=2. Remarkably, the Fano factor of the shot noise approaches to half when the bias energy is less than the superconducting gap, whereas it is close to zero above the superconducting gap. This is striking, given that, at the same time the electrical conductance remains at 2e2/h within and above the superconducting gap. These observations are in accord with our theoretical analysis based on non-equilibrium Green’s function (NEGF) calculation with disorders, pointing to complete de-phasing of interference of AESs along the QH-SC interface. Our results with unambiguous evidence of AESs at the QH-SC interface pave the way forward to explore the exotic topological excitations in QH-SC hybrids.

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Presenters

  • Manas Ranjan Sahu

    • Indian Institute of Science Bangalore

Authors

  • Manas Ranjan Sahu

    • Indian Institute of Science Bangalore

  • Arup Kumar Paul

    • Indian Institute of Science Bangalore

  • Jagannath Sutradhar

    • Indian Institute of Science Bangalore

  • Kenji Watanabe

    • National Institute for Materials Science
    • National Institute for Materials Science, Japan
    • National Institure for Materials Science
    • Advanced Materials Laboratory, National Institute for Materials Science
    • NIMS
    • National Institute of Materials Science
    • National Institute for Materials Science (NIMS)
    • Research Center for Functional Materials, National Institute for Materials Science
    • National Institute for Materials Science,1-1 Namiki
    • National Institute of Material Science
    • National Institute for Materials Science, Tsukuba, Japan
    • Research Center for Functional Materials, NIMS
    • National Institute of Materials Science, Tsukuba, Japan
    • National Institude for Materials Science
    • National Institute for Materials Science, Tsukuba, Ibaraki, Japan
    • Research Center for Functional Materials, National Institute for Materials Science, Tsukuba 305-0044, Japan
    • International Center for Materials Nanoarchitectonics, National Institute for Materials
    • NIMS - Japan
    • National Institute for Materials Science ,Japan
    • National Institute for Materials Science, Tsukuba, 305-0044, Ibaraki, Japan
    • National Institute for Material Science
    • National Institute for Material Science, 1-1 Namiki, Tsukuba 305-0044, Japan
    • National Institute for Material Science Japan
    • NIMS Tsukuba
    • National Institute for Materials Science, Research Center for Functional Materials, Japan
    • Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
    • National Institute for Materials Science: Namiki, Tsukuba, Ibaraki, JP
    • National Institue for Material Science
    • National Institute for Materials Science,1-1 Namiki, Tsukuba, 305-0044, Japan
    • Materials, NIMS
    • Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan, Research Center for Functional Materials, National In
    • Research Center for Functional Materials, Japan
    • International Center for Materials Nanoarchitectonics, National Institute for Materials Science
    • International Center for Materials nanoarchtectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
    • NIMS Suguba
    • NIMS, Tsukuba, Japan
    • National Institute for Materials Science, Namiki 1-1, Tsukuba, 305-0044, Ibaraki, Japan
    • National institute of material science
    • Advanced Materials Laboratory, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
    • Advanced Materials Laboratory, NIMS
    • Research Center for Functional Materials, National Institute for Materials Science, Ibaraki, Japan
    • National Institute for Materials Science, Research Center for Functional Materials
    • National Institute of Material Science, Japan
    • Tsukuba, National Institute for Materials Science

  • Takashi Taniguchi

    • National Institute for Materials Science
    • National Institute for Materials Science, Japan
    • National Institure for Materials Science
    • Advanced Materials Laboratory, National Institute for Materials Science
    • NIMS
    • National Institute of Materials Science
    • National Institute for Materials Science (NIMS)
    • International Center for Materials Nanoarchitectonics, National Institute for Materials Science
    • National Institute for Materials Science,1-1 Namiki
    • National Institute of Material Science
    • National Institute for Materials Science, Tsukuba, Japan
    • International Center for Materials Nanoarchitectonics, NIMS
    • Research Center for Functional Materials, National Institute for Materials Science
    • National Institute of Materials Science, Tsukuba, Japan
    • National Institude for Materials Science
    • International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba 305-0044, Japan
    • International Center for Materials Nanoarchitectonics, National Institute for Materials
    • NIMS - Japan
    • National Institute for Materials Science ,Japan
    • National Institute for Materials Science, Tsukuba, 305-0044, Ibaraki, Japan
    • National Institute for Material Science
    • National Institute for Material Science, 1-1 Namiki, Tsukuba 305-0044, Japan
    • National Institute for Material Science Japan
    • 8International Center for Materials Nanoarchitectonics
    • NIMS Tsukuba
    • National Institute for Materials Science: Namiki, Tsukuba, Ibaraki, JP
    • National Institue for Material Science
    • National Institute for Materials Science,1-1 Namiki, Tsukuba, 305-0044, Japan
    • Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan, Research Center for Functional Materials, National In
    • Research Center for Functional Materials, Japan
    • Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
    • International Center for Material Nanoarchitectonics, National Institute for Materials Science
    • International Center for Materials Nanoarchitectonics
    • NIMS Suguba
    • NIMS, Tsukuba, Japan
    • National Cheng Kung University
    • National Institute for Materials Science, Namiki 1-1, Tsukuba, 305-0044, Ibaraki, Japan
    • National institute of material science
    • Advanced Materials Laboratory, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
    • Advanced Materials Laboratory, NIMS
    • National Institute for Materials Science, International Center for Materials Nanoarchitectonics
    • National Institute of Material Science, Japan
    • Tsukuba, National Institute for Materials Science

  • Vibhor Singh

    • Indian Institute of Science Bangalore

  • Subroto Mukerjee

    • Indian Institute of Science Bangalore

  • Sumilan Banerjee

    • Indian Institute of Science Bangalore

  • Anindya Das

    • Indian Institute of Science Bangalore
    • Department of Physics, Indian Institute of Science, Bengaluru