Non-Reciprocal Supercurrents in a Field-Free Graphene Josephson Triode

TL;DR

This paper introduces a graphene-based Josephson triode that achieves high-efficiency non-reciprocal supercurrents at zero magnetic field, potentially useful for quantum circuits.

Contribution

It presents a novel graphene Josephson junction network device that operates without magnetic fields and demonstrates high efficiency in supercurrent rectification.

Findings

Achieves over 90% efficiency in supercurrent rectification.

Operates at zero magnetic field, unlike previous devices.

Demonstrates potential application in quantum circuits.

Abstract

Superconducting diodes are proposed non-reciprocal circuit elements that should exhibit non-dissipative transport in one direction while being resistive in the opposite direction. Multiple examples of such devices have emerged in the past couple of years, however their efficiency is typically limited, and most of them require magnetic field to function. Here we present a device achieving efficiencies upwards of 90% while operating at zero field. Our samples consist of a network of three graphene Josephson junctions linked by a common superconducting island, to which we refer as a Josephson triode. The triode is tuned by applying a control current to one of the contacts, thereby breaking the time-reversal symmetry of the current flow. The triode's utility is demonstrated by rectifying a small (tens of nA amplitude) applied square wave. We speculate that devices of this type could be realistically employed in the modern quantum circuits.