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Local Control of Supercurrent Density in Epitaxial Planar Josephson Junctions
Bassel Heiba Elfeky1, Neda Lotfizadeh1, William F Schiela1
1Department of Physics, New York University, New York, New York 10003, United States.
Nano Letters
|September 27, 2021
Summary
Researchers demonstrate local control over current distribution in Al-InAs Josephson junctions using minigates. This allows for electrostatic tuning of superconducting quantum interference devices and elimination of edge conduction for uniform current flow.
Area of Science:
- Superconducting electronics
- Mesoscopic physics
- Semiconductor heterostructures
Background:
- Josephson junctions are key components in superconducting electronics.
- Current distribution uniformity is crucial for device performance.
- Semiconducting weak links in Josephson junctions allow electrostatic tuning.
Purpose of the Study:
- To demonstrate local control of current distribution in epitaxial Al-InAs Josephson junctions.
- To show electrostatic definition of junction width and current profile.
- To investigate the formation of superconducting quantum interference devices (SQUIDs) and eliminate edge conduction.
Main Methods:
- Fabrication of epitaxial Al-InAs Josephson junctions with five integrated minigates.
- Application of out-of-plane magnetic fields to probe critical current response.
- Electrostatic gating to locally modify carrier density and current distribution.
Main Results:
- Minigates enable precise electrostatic control over the current distribution.
- Junction width and current profile can be tailored for SQUID formation.
- Enhanced edge conduction in long junctions is observed and can be suppressed by minigates.
- Achieved a uniform current distribution through electrostatic tuning.
Conclusions:
- Local electrostatic control via minigates offers a powerful method for tuning Josephson junction properties.
- This technique allows for the creation of custom current profiles, essential for advanced superconducting devices like SQUIDs.
- Elimination of edge conduction leads to improved uniformity and performance in long Josephson junctions.
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