Andreev bound state at a strongly correlated oxide interface

ORAL

Abstract

Strongly correlated electrons at oxide interfaces give rise to a set of novel physics phenomena including superconductivity and magnetism. At the LaAlO$_3$/SrTiO$_3$ (LAO/STO) interface, signatures of strong electron pairing persist even for conditions where superconductivity is suppressed. Meanwhile, an Andreev bound state (ABS) is a single quasiparticle excitation that mediates pair transport in confined superconductor-normal systems. Here we report a transition from pair resonant transport to ABS in sketched single electron transistors at the LAO/STO interface. This transition is consistent with a change of electron-electron interaction from attractive to repulsive, occurring at or near the Lifshitz transition. Such new electronically tunable electron-electron interaction may be useful for quantum simulation and engineering of novel quantum states in oxide materials.

*We gratefully acknowledge support from AFOSR FA9550-10-1-0524 (JL, CBE), AFOSR FA9550-12-1-0057 (JL, CBE, AD), NSF DMR-1104191 (JL), ONR N00014-15-1-2847 (JL).

–

Authors

  • Guanglei Cheng

    • Univ. of Pittsburgh

  • Michelle Tomczyk

    • Univ of Pittsburgh
    • Univ. of Pittsburgh

  • Alexandre Tacla

    • Department of Physics and SUPA, University of Strathclyde
    • Univ. of Strathclyde

  • Andrew Daley

    • Department of Physics and SUPA, University of Strathclyde
    • Univ of Strathclyde
    • Univ. of Strathclyde

  • Shicheng Lu

    • Univ. of Pittsburgh

  • Josh Veazey

    • Univ. of Pittsburgh

  • Mengchen Huang

    • University of Pittsburgh
    • Univ. of Pittsburgh
    • Univ of Pittsburgh

  • Patrick Irvin

    • University of Pittsburgh
    • Univ. of Pittsburgh
    • Univ of Pittsburgh

  • Sangwoo Ryu

    • Univ. of Wisconsin-Madison
    • Department of Materials Science and Engineering, University of Wisconsin, Madison, Wisconsin 53706, USA

  • Hyungwoo Lee

    • University of Wisconsin - Madison
    • Univ. of Wisconsin-Madison
    • University of Wisconsin-Madison
    • Department of Materials Science and Engineering, University of Wisconsin, Madison, Wisconsin 53706, USA

  • Chang-Beom Eom

    • University of Wisconsin-Madison
    • University of Wisconsin - Madison
    • Univ. of Wisconsin-Madison
    • Department of Materials Science and Engineering, University of Wisconsin, Madison, Wisconsin 53706, USA

  • David Pekker

    • Department of Physics and Astronomy, University of Pittsburgh
    • University of Pittsburgh
    • Univ. of Pittsburgh

  • Jeremy Levy

    • University of Pittsburgh
    • Univ. of Pittsburgh