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Updated: Sep 21, 2025

Scanning SQUID Study of Vortex Manipulation by Local Contact
Published on: February 1, 2017
Quasiparticle Trapping at Vortices Producing Josephson Supercurrent Enhancement
Yosuke Sato1,2, Kento Ueda1, Yuusuke Takeshige1
1Department of Applied Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
Abstract:
The Josephson junction of a strong spin-orbit material under a magnetic field is a promising Majorana fermion candidate. Supercurrent enhancement by a magnetic field has been observed in the InAs nanowire Josephson junctions and assigned to a topological transition. In this work we observe a similar phenomenon but discuss the nontopological origin by considering the trapping of quasiparticles by vortices that penetrate the superconductor under a finite magnetic field. This assignment is supported by the observed hysteresis of the switching current when sweeping up and down the magnetic field. Our experiment shows the importance of quasiparticles in superconducting devices with a magnetic field, which can provide important insights for the design of qubits using superconductors.
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