Nonreciprocal Supercurrents in a Field-Free Graphene Josephson Triode

Superconducting diodes are proposed nonreciprocal circuitelementsthat should exhibit nondissipative transport in one direction whilebeing resistive in the opposite direction. Multiple examples of suchdevices have emerged in the past couple of years; however, their efficiencyis typically limited, and most of them require a magnetic field tofunction. Here we present a device that achieves efficiencies approaching100% while operating at zero field. Our samples consist of a networkof three graphene Josephson junctions linked by a common superconductingisland, to which we refer as a Josephson triode. The three-terminalnature of the device inherently breaks the inversion symmetry, andthe control current applied to one of the contacts breaks the time-reversalsymmetry. The triode's utility is demonstrated by rectifyinga small (nA scale amplitude) applied square wave. We speculate thatdevices of this type could be realistically employed in the modernquantum circuits.

Automated summary

This article introduces a device using superconducting diodes as non-reciprocal circuit elements, which enables non-dissipative transport in one direction and resistive transport in the opposite direction. The device consists of three graphene Josephson junctions connected by a common superconducting island, referred to as a Josephson triode. By breaking the time-reversal symmetry with a control current, the device achieves efficiencies approaching 100% without the need for a magnetic field. The utility of the triode is demonstrated by rectifying a small amplitude square wave, indicating its potential application in modern quantum circuits.