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Gate-tunable superconducting diode effect in a three-terminal Josephson device
Mohit Gupta1, Gino V Graziano1, Mihir Pendharkar2,3
1School of Physics and Astronomy, University of Minnesota, Minneapolis, MN, 55455, USA.
Nature Communications
|May 29, 2023
Summary
Researchers observed the Josephson diode effect in a novel three-terminal device. This effect, a non-reciprocal critical current, can be tuned, paving the way for scalable quantum technologies.
Area of Science:
- Condensed Matter Physics
- Quantum Electronics
- Materials Science
Background:
- The Josephson diode effect, a non-reciprocal critical current in Josephson devices, requires breaking inversion symmetry.
- Spin-orbit interactions are typically employed to achieve this symmetry breaking.
Purpose of the Study:
- To report the observation of the Josephson diode effect in a novel three-terminal Josephson device.
- To investigate the tunability and underlying mechanisms of this effect.
- To establish a scalable approach for Josephson diode applications.
Main Methods:
- Fabrication of a three-terminal Josephson device using an InAs quantum well and an epitaxial aluminum superconducting layer.
- Characterization of the Josephson diode effect through measurements of critical current non-reciprocity.
- Tuning of the diode efficiency using an out-of-plane magnetic field and electrostatic gating.
Main Results:
- Observation of the Josephson diode effect in the fabricated device.
- Demonstration that diode efficiency is tunable via magnetic field and electrostatic gating.
- Identification of a higher-harmonic current-phase relation as the cause of the diode effect.
- Observation of nonlinear DC intermodulation and two-signal rectification due to the multi-terminal nature.
Conclusions:
- The Josephson diode effect is an inherent property of multi-terminal Josephson devices.
- This work establishes a scalable platform for realizing the Josephson diode effect, independent of specific material platforms.
- These devices offer potential as gate-tunable building blocks for topological qubits.
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