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Majorana π-junctions in full-shell nanowire SQUIDs

ORAL

Abstract

Recent studies of InAs nanowires covered by full-shell Al superconductor showed signatures of Majorana zero modes (MZMs) around one applied axial-flux quantum [1]. Here, we study such wires in dc-SQUID geometry with a naturally-formed normal quantum dots in the Josephson junctions. In the trivial regime around zero axial-flux we find 0-π transition as the occupancy of a quantum dot is changed; the transition vanishes at one axial-flux quantum. In addition, we find that the critical currents of the Josephson junctions increase in the topological regime. Tunneling spectroscopy of a junction in the π-state reveals a discrete zero-energy state at one applied axial-flux quantum. Our observations are consistent with the theoretical models of MZMs coupling through a normal quantum dot [2,3].

[1] S. Vaitiekenas et al. arxiv:1809.05513
[2] C. Schrade and L. Fu arxiv:1809.06370
[3] J. Schulenborg and K. Flensberg. arxiv:1910.04106

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Presenters

  • Davydas Razmadze

    Niels Bohr Institute, University of Copenhagen

Authors

  • Davydas Razmadze

    Niels Bohr Institute, University of Copenhagen

  • Eoin C O'Farrell

    Niels Bohr Institute, University of Copenhagen

  • Peter Krogstrup

    Niels Bohr Institute, University of Copenhagen, University of Copenhagen, Center for Quantum Devices and Microsoft Quantum Lab--Copenhagen, Niels Bohr Institute, University of Copenhagen, Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen

  • Charles Marcus

    Center for Quantum Devices and Microsoft Quantum Lab Copenhagen, Niels Bohr Institute, University of Copenhagen, Microsoft Quantum Lab Copenhagen and Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark, Univ of Copenhagen, Center for Quantum Devices and Microsoft Quantum Lab - Copenhagen, University of Copenhagen, Center for Quantum Devices, Microsoft Quantum Lab – Copenhagen and Niels Bohr Institute, University of Copenhagen, Microsoft Corp, Niels Bohr Institute, University of Copenhagen