Observation of perfect Andreev reflection due to Klein paradox in a topological superconducting state in SmB<sub>6</sub>/YB<sub>6</sub> heterostructures

ORAL

Abstract

Topological insulator, whose boundary states are described by the massless Dirac equation, is of great interest to realize unusual states of quantum matter. We report the observation of perfect Andreev reflection as a manifestation of Klein tunneling (perfect transmission of massless Dirac particles through any potential barrier) at the interface between a normal metal and a SmB6/YB6 heterostructure. We have previously demonstrated proximity-induced superconductivity in the surface state of SmB6. Conductance spectra of point contact junctions between a PtIr tip and the surface of the superconducting SmB6 show perfect conductance doubling within the induced superconducting gap (Δ). The absence of electron reflection under such finite Z is attributed to the interplay of the Dirac material in Andreev reflection process i.e., Klein tunneling. The observation can be described by a modified BTK theory with Dirac Hamiltonian, Dirac-BTK theory.

*This work was funded by ONR N00014-13-1-0635, ONR N00014-15-1-2222, AFOSR No. FA9550-14-10332, and C-SPIN.

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Presenters

  • Seunghun Lee

    • University of Maryland, College Park

Authors

  • Seunghun Lee

    • University of Maryland, College Park

  • Valentin Stanev

    • University of Maryland, College Park

  • Xiaohang Zhang

    • University of Maryland, College Park

  • Joshua S Higgins

    • University of Maryland, College Park

  • Victor M Yakovenko

    • University of Maryland, College Park

  • Johnpierre Paglione

    • Physics, University of Maryland
    • University of Maryland, College Park
    • Center for Nanophysics and Advanced Materials, University of Maryland College Park
    • Center for Nanophysics and Advance Materials, University of Maryland, College Park, MD
    • University of Maryland, College Park & NIST
    • Department of Physics, University of Maryland, College Park
    • University of Maryland
    • University of Maryland - College Park

  • Richard L. Greene

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

  • Victor Galitski

    • University of Maryland, College Park

  • Ichiro Takeuchi

    • Materials Science and Engineering, University of Maryland
    • University of Maryland
    • University of Maryland, College Park
    • Materials Science & Engineering Dept, University of Maryland