Experimental signatures of Majorana bound states in S-TI-S lateral Josephson junctions

ORAL

Abstract

We present experiments designed to search for features of Majorana bound states (MBS) in lateral Josephson junctions formed by depositing s-wave superconductors onto the surface of topological insulator thin films. In a vertical magnetic field that induces a phase gradient across the junction, the localized MBS are expected to be stable at the cores of Josephson vortices where the phase difference across the junction is an odd multiple of π. To test this picture, we have fabricated Nb-Bi2Se3-Nb Josephson junctions with different geometries and carried out extensive measurements of their Josephson supercurrent vs. magnetic field diffraction patterns and the statistical critical current switching distribution in hysteretic junctions. Our results show a number of expected features of MBS, including: (1) finite critical current at the location of odd-numbered nodes of the diffraction pattern, (2) anomalous critical current distributions characterized by either a double peak in the switching distribution or an increase in the standard deviation of the distribution changes at values of magnetic field at which MBS are expected to be present in the junction. We will present a compilation of our data and analysis of these experiments.

*NSF DMR 16-10114

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Presenters

  • Guang Yue

    • University of Illinois at Urbana-Champaign
    • Physics, University of Illinois Urbana Champaign

Authors

  • Guang Yue

    • University of Illinois at Urbana-Champaign
    • Physics, University of Illinois Urbana Champaign

  • Can Zhang

    • University of Illinois at Urbana-Champaign

  • Erik Huemiller

    • Physics, University of Illinois at Urbana-Champaign
    • Inprentus Precision Optics
    • Physics, University of Illinois Urbana Champaign
    • University of Illinois at Urbana-Champaign

  • Maryam Salehi

    • Rutgers, the State University of New Jersey
    • Materials Science and Engineering, Rutgers, The State University of New Jersey
    • Materials Sci. & Eng., Rutgers University
    • Rutgers University, New Brunswick
    • Rutgers University
    • Rutgers University - New Brunswick

  • Nikesh Koirala

    • Massachusetts Institute of Technology
    • Physics and Astronomy, Rutgers, The State University of New Jersey
    • Rutgers University - New Brunswick

  • Seongshik Oh

    • Rutgers, the State University of New Jersey
    • Center for Quantum Materials Synthesis and Department of Physics and Astronomy, Rutgers, the State University of New Jersey
    • Physics and Astronomy, Rutgers, The State University of New Jersey
    • Physics, Rutgers University
    • Physics, Rutgers, The State University of New Jersey
    • Rutgers University
    • Rutgers University - New Brunswick

  • Alexey Bezryadin

    • Physics, University of Illinois at Urbana-Champaign
    • University of Illinois at Urbana-Champaign

  • Dale J Van Harlingen

    • University of Illinois at Urbana-Champaign
    • Physics, University of Illinois Urbana Champaign