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Phase signature of topological transition in Josephson junctions

ORAL

Abstract

Topological transition transforms common superconductivity into an exotic phase of matter, which holds promise for fault-tolerant quantum computing. A hallmark of this transition is the emergence of Majorana states. While two-dimensional semiconductor/superconductor heterostructures are desirable platforms for topological superconductivity, direct phase-measurements as the fingerprint of the underlying topological transition have been missing.
On gate tunable Josephson junctions made on epitaxial Al/InAs, we observe a closing and a reopening of the superconducting gap with increasing in-plane magnetic field. Since our junctions are embedded into a phase-sensitive SQUID, we are able to measure a π-jump in the superconducting phase across the junction coincident with the closing and reopening of the superconducting gap. Theoretical simulations confirm this transition is topological and compatible with the emergence of Majorana states while the magnetic field angle dependence of the transition further constrain this scenario. Remarkably, in each junction, this topological transition can be controlled by changing the gate voltage. These findings reveal versatile two-dimensional platforms for scalable topological quantum computing.

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Presenters

  • Matthieu Dartiailh

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

Authors

  • Matthieu Dartiailh

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

  • William Mayer

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

  • Joseph Yuan

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

  • Kaushini S Wickramasinghe

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

  • Alex Matos Abiague

    Wayne State Univ, Department of Physics and Astronomy, Wayne State University, Wayne State University, Physics and Astronomy, Wayne State University

  • Igor Zutic

    Department of Physics, State Univ of NY - Buffalo, University at Buffalo, Physics, Buffalo State Univeristy of New York, Department of Physics, State University at New York at Buffalo, State Univ of NY - Buffalo, Physics, University at Buffalo, State University of New York, Department of Physics, University at Buffalo, Department of physics, University at Buffalo

  • Javad Shabani

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