Shapiro steps in InAs-based Josephson junctions with epitaxial Al contacts

ORAL

Abstract

Semiconductor-based Josephson junction provide a platform to study the proximity effect and can serve as a platform for the realization of in topological superconductivity. Recently our group has demonstrated the possibility to have a highly transparent contact between the superconductor and the semiconductor by combining InAs high mobility surface 2D-dimensional electron gases with epitaxially grown aluminium.
The interplay between the induced superconducting gap and the spin-orbit coupling in those structure is still an on-going field of research. While DC measurements can allow to access the current-phase relation of those structure, some details could be masked by relaxation processes. We utilize microwave radiation on Josephson junctions to unmask the periodicity of the current phase relation. We study Shapiro steps that appear in the IV characteristic of a junction under microwave irradiation. We observe a missing first Shapiro step below 6 GHz that may point to a 4π component in the current-phase relation of those junctions. Similar signatures have been observed in HgTe (in the topological regime) but given the high transparency of our contacts they may arise from Landau-Zener transitions in our InAs structures.

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Presenters

  • Matthieu Dartiailh

    Physics, New York University, Center for Quantum Phenomena, Department of Physics, New York University, Laboratoire Pierre Aigrain UMR 8551, Ecole normale Supérieure - PSL Research university, CNRS, Université Pierre et Marie Curie - Sorbonne Universités, Université Paris Dider

Authors

  • Matthieu Dartiailh

    Physics, New York University, Center for Quantum Phenomena, Department of Physics, New York University, Laboratoire Pierre Aigrain UMR 8551, Ecole normale Supérieure - PSL Research university, CNRS, Université Pierre et Marie Curie - Sorbonne Universités, Université Paris Dider

  • Joseph Yuan

    Department of Physics, New York University, Physics, New York University, Center for Quantum Phenomena, Department of Physics, New York University

  • William Andrew Mayer

    Department of Physics, New York University, Physics, New York University, Center for Quantum Phenomena, Department of Physics, New York University

  • Kaushini Wickramasinghe

    University of Oklahoma, Department of Physics, New York University, Physics, New York University, Physics, University of Maryland, College Park, Center for Quantum Phenomena, Department of Physics, New York University, University of Maryland, College Park

  • Dillon Liu

    Physics, New York University, Center for Quantum Phenomena, New York University

  • Aditi Mitra

    Physics, New York University, New York University, Center for Quantum Phenomena, New York University

  • Javad Shabani

    Department of Physics, New York University, Physics, New York University, Center for Quantum Phenomena, Department of Physics, New York University, Center for Quantum Phenomena, New York University, New York University, Physics, Harvard University