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Gate controlled anomalous phase shift in Al/InAs Josephson junctions
William Mayer1, Matthieu C Dartiailh1, Joseph Yuan1
1Center for Quantum Phenomena, Department of Physics, New York University, New York, NY, 10003, USA.
Nature Communications
|January 12, 2020
Summary
Researchers observed a tunable anomalous Josephson effect in InAs/Al junctions. Gate control of InAs density tunes spin-orbit coupling, enabling control over the anomalous phase for superconducting spintronics and topological superconductivity research.
Area of Science:
- Condensed Matter Physics
- Superconducting Spintronics
- Quantum Phenomena
Background:
- Standard Josephson junctions exhibit zero supercurrent at zero phase difference, protected by symmetry.
- Spin-orbit coupling and magnetic fields break these symmetries, enabling anomalous Josephson effects.
- The anomalous Josephson effect is crucial for superconducting spintronics and topological superconductivity.
Purpose of the Study:
- To experimentally observe and control the anomalous Josephson effect.
- To demonstrate gate-tunable spin-orbit coupling in InAs/Al Josephson junctions.
- To explore new avenues for superconducting spintronics and topological superconductivity.
Main Methods:
- Fabrication of InAs/Al Josephson junctions.
- Measurement using a superconducting quantum interference device (SQUID).
- Gate voltage control to tune InAs carrier density and spin-orbit coupling strength.
Main Results:
- Observation of a tunable anomalous Josephson effect.
- Demonstration of gate-controlled anomalous phase shift.
- Correlation between InAs density, spin-orbit coupling, and anomalous phase.
Conclusions:
- The tunable anomalous Josephson effect is achievable in InAs/Al systems.
- Gate-tunable spin-orbit coupling offers precise control over superconducting spintronic properties.
- This work paves the way for novel superconducting spintronic devices and topological quantum computations.
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