Interference effects in quanum Hall - superconductor hybrid devices

 · Invited

Abstract

I plan to discuss our group’s two recent results: realization of the quantum Hall-based SQUID in side-gated samples; and observation of the chiral Andreev edge states – hybrid electron/hole single particle modes running along the superconductor - quantum Hall interfaces.

1) We have developed graphene Josephson junctions with self-aligned side gates, which enable full control over the electrostatic potential near the sample edges. The gates allow us to tune the local electron density in a wide range, in particular inducing counterpropagating quantum Hall edge states along either side gate. The close spacing between these states allows them to efficiently couple through Andreev reflections and carry supercurrent. When both side gates are applied, superconducting channels are created on both sides of the junction, thereby realizing a gate-tunable quantum Hall-based SQUID.

2) We observe direct signatures of chiral Andreev edge states (CAES) – single particle modes running along the superconductor - quantum Hall interfaces. Semi-classically, the CAES can be interpreted as a result of multiple Andreev reflections of a single electron/hole skipping along the interface. Experimentally, we observe fluctuations of the signal propagating along the superconducting contact and interpret them in terms of interference between the CAES.

*Transport measurements conducted by L.Z., E.G.A., and A.S. were supported by the DOE Award No. de-sc0002765. Lithographic fabrication and samples characterization was performed by L.Z., M.-T. W., and A.S. with the support of NSF awards ECCS-1610213 and DMR-1743907. The measurement setup was developed by A.W.D., T.L., and G.F. with the support of ARO Award W911NF-16-1-0122. Numerical simulations conducted by A.B. and H.U.B. were supported by the DOE Award No. de-sc0005237. H.L. and F.A. acknowledge the ARO Award W911NF-16-1- 0132. K.W. and T.T. acknowledge support from JSPS KAKENHI Grant Number JP15K21722.

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Presenters

  • Gleb Finkelstein

    • Duke University
    • Department of Physics, Duke University
    • Physics, Duke University

Authors

  • Gleb Finkelstein

    • Duke University
    • Department of Physics, Duke University
    • Physics, Duke University

  • Andrew Seredinski

    • Duke University
    • Department of Physics, Duke University
    • Physics, Duke University

  • Lingfei Zhao

    • Duke University
    • Department of Physics, Duke University
    • Physics, Duke University

  • Ethan Arnault

    • Duke University
    • Department of Physics, Duke University
    • Physics, Duke University

  • Anne M Draelos

    • Duke University

  • Alexey Bondarev

    • Duke University

  • Trevyn Larson

    • Duke University
    • Department of Physics, Duke University
    • Physics, Duke University

  • Ming-Tso Wei

    • Duke University
    • University of Maryland, College Park
    • Physics, University of Maryland

  • Hengming Li

    • Physics, Appalachian State University
    • Appalachian State University
    • Department of Physics and Astronomy, Appalachian State University

  • Kenji Watanabe

    • National Institute for Materials Science, Japan
    • National Institute for Material Science
    • National Institute for Materials Science
    • National Institute for Materials Science, Tsukuba
    • Research Center for Functional Materials, NIMS
    • nims
    • Advanced Materials Laboratory, National Institute for Materials Science
    • National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
    • NIMS
    • National Institute for Material Science - Japan
    • NIMS Tsukuba
    • National Institute for Materials Science, Namiki 1-1, Ibaraki 305-0044, Japan.
    • National Institute for Materials Science (NIMS)
    • National Institute for Materials Science,Tsukuba, Ibaraki 305-0047, Japan
    • Advanced Materials Laboratory, NIMS, Japan
    • National Institute for Materials Science,1-1 Namiki, Tsukuba, 305-0044, Japan
    • National Institute of Materials Science
    • National Institute for Materials Science, University of Tsukuba
    • National Institute for Materials Science, Tsukuba, Japan
    • National Institute for Material Science, Japan
    • National Institue for Material Science, Tsukuba
    • Advanced Materials Laboratory, NIMS
    • Advanced Materials Laboratory, National Institute for Materials Science, Tsukuba 305-0044, Japan
    • Advanced Matrials Lab, NIMS
    • National Institute for Material Science, Tsukuba, Japan
    • National institute for materials science
    • NIMS-Tsukuba
    • NIMS, Japan
    • National Institute for Materials Science, Namiki Tsukuba Ibaraki, Japan
    • NIRM
    • Advanced Materials Laboratory, National Institute for Materials Science, Tsukuba, Japan
    • NIMS Japan
    • National Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan
    • Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Ibaraki, Japan
    • Advanced Materials Laboratory, National Institute of Materials Science
    • Advanced Materials Laboratory, National Institute for Materials Science 1-1 Namiki, Tsukuba, 305-0044, Japan
    • National Institute of Material Science, 1-1 Namiki, Tsukuba 305-0044, Japan
    • National Institute for Material Science (Japan)
    • Physics, NIMS
    • National Institute of Materials Science, Japan
    • National Institute of Materials Science (NIMS)
    • National Institute of Materials Science, Tsukuba, Ibaraki 305-0044, Japan
    • NIMS - Tsukuba

  • Takashi Taniguchi

    • National Institute for Materials Science, Japan
    • National Institute for Material Science
    • National Institute for Materials Science
    • National Institute for Materials Science, Tsukuba
    • Research Center for Functional Materials, NIMS
    • nims
    • Advanced Materials Laboratory, National Institute for Materials Science
    • National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
    • NIMS
    • National Institute for Material Science - Japan
    • NIMS Tsukuba
    • National Institute for Materials Science, Namiki 1-1, Ibaraki 305-0044, Japan.
    • National Institute for Materials Science (NIMS)
    • National Institute for Materials Science,Tsukuba, Ibaraki 305-0047, Japan
    • Advanced Materials Laboratory, NIMS, Japan
    • National Institute for Materials Science,1-1 Namiki, Tsukuba, 305-0044, Japan
    • National Institute of Materials Science
    • National Institute for Materials Science, University of Tsukuba
    • National Institute for Materials Science, Tsukuba, Japan
    • National Institue for Material Science, Tsukuba
    • Advanced Materials Laboratory, NIMS
    • Advanced Materials Laboratory, National Institute for Materials Science, Tsukuba 305-0044, Japan
    • Advanced Matrials Lab, NIMS
    • National Institute for Material Science, Tsukuba, Japan
    • National institute for materials science
    • NIMS-Tsukuba
    • NIMS, Japan
    • National Institute for Materials Science, Namiki Tsukuba Ibaraki, Japan
    • Advanced Materials Laboratory, National Institute for Materials Science, Tsukuba, Japan
    • NIMS Japan
    • National Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan
    • Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Ibaraki, Japan
    • Advanced Materials Laboratory, National Institute of Materials Science
    • Advanced Materials Laboratory, National Institute for Materials Science 1-1 Namiki, Tsukuba, 305-0044, Japan
    • National Institute of Material Science, 1-1 Namiki, Tsukuba 305-0044, Japan
    • National Institute for Material Science (Japan)
    • Physics, NIMS
    • National Institute of Materials Science, Japan
    • National Institute of Materials Science, Tsukuba, Ibaraki 305-0044, Japan
    • NIMS - Tsukuba

  • Francois Amet

    • Physics, Appalachian State University
    • Appalachian State University
    • Department of Physics and Astronomy, Appalachian State University
    • Department of Physics and Astronomy, Appalachian State University, Boone, NC, USA
    • Appalachian State

  • Harold U Baranger

    • Duke University