Tunable diode effect in a superconducting tunnel junction with biharmonic drive

TL;DR

This paper demonstrates that a biharmonic drive applied to a standard superconducting tunnel junction can induce a tunable diode effect through harmonic mixing, enabling non-reciprocal supercurrent flow without complex materials or circuits.

Contribution

It introduces a novel method to achieve a Josephson diode effect using biharmonic driving on conventional junctions, avoiding complex material engineering.

Findings

Unity efficiency in diode operation is achievable in conventional junctions.

The diode's directionality can be tuned in situ by adjusting the phase between driving tones.

Harmonic mixing shifts the supercurrent region, enabling non-reciprocal transport.

Abstract

A Josephson diode is a superconducting circuit element that enables non-reciprocal transport, allowing a dissipationless supercurrent to preferentially flow in a single direction. Existing methods for achieving the required symmetry breaking mostly rely on specifically-designed materials or carefully-engineered circuits composed of multiple Josephson junctions. Here, we demonstrate that applying a biharmonic drive to a conventional superconducting tunnel-junction induces a diode effect through harmonic mixing processes that shift the supercurrent region. We show that, in a conventional tunnel junction, unity efficiency is achievable while maintaining a large supercurrent. Moreover, the relative phase between the two driving tones determines the directionality of the diode, which can be tuned in situ.