Flux-Dependent Superconducting Diode Effect in an Aharonov-Bohm Interferometer.

Area of Science:

• Condensed Matter Physics
• Quantum Electronics
• Nanotechnology

Background:

• Superconducting diode effect (SDE) enables nonreciprocal charge transport in superconductors.
• Aharonov-Bohm (AB) interferometers offer a platform to control quantum interference phenomena.

Purpose of the Study:

• To theoretically investigate the SDE in an AB interferometer with a quantum dot (QD).
• To explore the role of quantum interference and time-reversal symmetry breaking in inducing SDE.
• To optimize diode efficiency by controlling transport pathways.

Main Methods:

• Theoretical modeling of an AB interferometer with an Indium Arsenide (InAs) QD in one arm.
• Analysis of supercurrents and Fano line shapes due to interference between Andreev bound states and continuous states.
• Investigation of the effect of magnetic flux on time-reversal symmetry and phase differences.

Main Results:

• The SDE is induced by magnetic flux modulating quantum phase differences, leading to asymmetric critical supercurrents.
• Critical supercurrents exhibit Fano line shapes resulting from interference effects.
• Maximum diode efficiency of 80% is achieved when QD transport dominates; efficiency weakens when the direct arm dominates due to higher-order interference.

Conclusions:

• The proposed AB interferometer design is simple and feasible with current nanofabrication.
• The study demonstrates a viable route to realize high-efficiency SDE in superconducting devices.
• This work contributes to the development of nonreciprocal superconducting electronic components.