Link between supercurrent diode and anomalous Josephson effect revealed by gate-controlled interferometry

TL;DR

This paper demonstrates a direct link between the anomalous Josephson effect and supercurrent diode behavior in Josephson junctions, showing that spin-orbit interaction and magnetic fields induce nonreciprocal supercurrents.

Contribution

It provides the first simultaneous measurement of the $oldsymbol{ extphi}_0$-shift and diode efficiency in a single Josephson junction, revealing their direct correlation via gate control.

Findings

Supercurrent diode effect is mainly due to magnetochiral anisotropy.

Gate voltage controls the $oldsymbol{ extphi}_0$-shift and diode efficiency.

Spin-orbit interaction combined with Zeeman field induces nonreciprocal supercurrents.

Abstract

In Josephson diodes the asymmetry between positive and negative current branch of the current-phase relation leads to a polarity-dependent critical current and Josephson inductance. The supercurrent nonreciprocity can be described as a consequence of the anomalous Josephson effect -- a $\varphi_0$-shift of the current-phase relation -- in multichannel ballistic junctions with strong spin-orbit interaction. In this work, we simultaneously investigate $\varphi_0$-shift and supercurrent diode efficiency on the same Josephson junction by means of a superconducting quantum interferometer. By electrostatic gating, we reveal a direct link between $\varphi_0$-shift and diode effect. Our findings show that the supercurrent diode effect mainly results from magnetochiral anisotropy induced by spin-orbit interaction in combination with a Zeeman field.