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Efficiency-Tunable Field-Free Josephson Diode Effect in Nb3Cl8 Based van der Waals Junctions
Si Li Wu1,2, Zhi-Hui Ren1,2, Liu Yang1,2
1Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing 100081, China.
Nano Letters
|December 12, 2025
Summary
We demonstrate a tunable magnetic field-free Josephson diode effect (JDE) in van der Waals heterostructures. Tuning barrier thickness and electric fields control diode efficiency by modulating intrinsic electric polarization.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Devices
Background:
- The Josephson diode effect (JDE) enables nonreciprocal current flow in superconducting devices.
- Understanding the microscopic origins and control mechanisms of field-free JDE is crucial for device applications.
- Van der Waals (vdW) heterostructures offer tunable electronic properties.
Purpose of the Study:
- To demonstrate and control a tunable, magnetic field-free Josephson diode effect (JDE).
- To investigate the role of intrinsic electric polarization in field-free JDE.
- To explore the potential of vdW heterostructures for nonreciprocal superconducting devices.
Main Methods:
- Fabrication of NbSe2/Nb3Cl8/NbSe2 vdW Josephson junctions with varying barrier thicknesses.
- Electrical transport measurements to characterize the Josephson diode effect.
- Application of out-of-plane electric fields to modulate junction properties.
Main Results:
- Significant enhancement of field-free JDE efficiency by reducing Nb3Cl8 barrier thickness (1.75% to 20.88%).
- Tunable diode efficiency via out-of-plane electric field, indicating intrinsic electric polarization.
- Correlation between polarization strength, barrier thickness, and electric field modulation of JDE.
Conclusions:
- Intrinsic electric polarization is key to realizing tunable, field-free JDE in vdW heterostructures.
- JDE in these junctions is sensitive to spontaneous time-reversal symmetry breaking.
- This work provides a pathway for designing advanced nonreciprocal superconducting devices.
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