Josephson diode effect derived from short-range coherent coupling

The behaviour of a superconductor can be altered by changing its symmetry properties. Coherently coupling two Josephson junctions breaks time-reversal and inversion symmetries, giving rise to a device with a controllable superconducting diode effect. Typical superconducting materials have both time-reversal symmetry and inversion symmetry. Devices that break these symmetries are expected to have exotic phenomena such as the superconducting diode effect, which can provide lossless rectification. Here, we present a device comprising one Josephson junction coupled to another that exhibits the superconducting diode effect. We show that the observed effect can be controlled non-locally based on the phase difference of the adjacent junction. These results indicate that the time-reversal and spatial-inversion symmetries of a Josephson junction are broken by the coherent coupling to an adjacent junction, and this enables the engineering of superconducting phenomena mediated by interaction among Josephson junctions.

Automated summary

The behaviour of a superconductor can be modified by changing its symmetry properties, specifically by breaking time-reversal and inversion symmetries through coupling Josephson junctions. Such devices can exhibit exotic phenomena, like the controllable superconducting diode effect, which enables lossless rectification. In this study, a device consisting of two coupled Josephson junctions demonstrates the superconducting diode effect, with control based on the phase difference of the adjacent junction. This breakthrough indicates the breaking of time-reversal and spatial-inversion symmetries in Josephson junctions, allowing for engineering of superconducting phenomena mediated by interaction among Josephson junctions.