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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.
Physical Review Letters
|June 3, 2022
Summary
We observed supercurrent enhancement in Josephson junctions, but attribute it to quasiparticle trapping, not a topological transition. Hysteresis in magnetic field sweeps supports this nontopological explanation for superconducting devices.
Area of Science:
- Condensed Matter Physics
- Quantum Materials
- Superconductivity
Background:
- Josephson junctions in strong spin-orbit materials are candidates for Majorana fermions.
- Supercurrent enhancement in InAs nanowire Josephson junctions under magnetic fields was previously attributed to topological transitions.
Purpose of the Study:
- To investigate the origin of supercurrent enhancement in magnetic field-exposed Josephson junctions.
- To explore the role of quasiparticles and vortices in observed superconducting phenomena.
Main Methods:
- Fabrication and characterization of InAs nanowire Josephson junctions.
- Measurement of supercurrent and switching current under varying magnetic fields.
- Analysis of magnetic field hysteresis in device performance.
Main Results:
- Observed supercurrent enhancement in Josephson junctions under magnetic fields.
- Demonstrated a nontopological origin for this enhancement, linked to quasiparticle trapping by vortices.
- Confirmed the role of quasiparticles through observed hysteresis in switching currents.
Conclusions:
- The observed supercurrent enhancement is likely due to nontopological effects, specifically quasiparticle trapping.
- Understanding quasiparticle behavior is crucial for designing robust superconducting qubits.
- This work provides insights into the physics of superconducting devices in magnetic fields.
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