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Zeeman- and Orbital-Driven Phase Shifts in Planar Josephson Junctions
Daniel Z Haxell1, Marco Coraiola1, Deividas Sabonis1
1IBM Research Europe-Zurich, 8803 Rüschlikon, Switzerland.
ACS Nano
|September 11, 2023
Summary
We observed gate-dependent phase shifts in InAs/Al Josephson junctions (JJs) due to magnetic fields. These shifts reveal insights into phase transitions and potential applications in quantum computing.
Area of Science:
- Condensed Matter Physics
- Quantum Information Science
Background:
- Josephson junctions (JJs) are crucial for superconducting electronics and quantum computing.
- Understanding phase transitions in hybrid JJs is essential for device development.
Purpose of the Study:
- Investigate phase shifts in the current-phase relation of InAs/Al JJs under in-plane magnetic fields.
- Elucidate the interplay of Zeeman, spin-orbit, and orbital effects in hybrid JJs.
- Explore signatures of induced phase transitions and their dependence on device geometry.
Main Methods:
- Supercurrent and tunneling spectroscopy measurements on gate-tunable InAs/Al Josephson junctions.
- Application of in-plane magnetic fields.
- Systematic study of devices with varying superconducting lead sizes to probe orbital effects.
Main Results:
- Observed gate-dependent phase shifts up to 0.5π at low fields, attributed to Rashba spin-orbit interaction and Zeeman coupling.
- Identified a distinct phase shift at higher fields, linked to a switching current minimum and superconducting gap modulation.
- Demonstrated that these phase transition signatures scale with superconducting lead size, highlighting the role of orbital effects.
Conclusions:
- The study elucidates the complex interplay of fundamental physical effects in hybrid Josephson junctions.
- Results provide a deeper understanding of phase transitions in InAs/Al JJs.
- Findings contribute to the advancement of quantum computing and superconducting electronics.
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