The superconducting diode effect in Josephson junctions fabricated from structurally chiral Mo$_3$Al$_2$C

TL;DR

This study demonstrates a magnetic field-induced superconducting diode effect in Josephson junctions made from structurally chiral Mo$_3$Al$_2$C, revealing how chirality and broken symmetries influence superconducting transport.

Contribution

It reports the first observation of a superconducting diode effect in Josephson junctions with chiral superconductor interfaces, highlighting the role of structural chirality in breaking symmetries.

Findings

Superconducting diode effect observed in right-handed/left-handed junctions.

Maximum diode asymmetry of 5% under magnetic field.

No diode effect in right-handed/right-handed junctions.

Abstract

The superconducting diode effect occurs in superconducting materials in which both spin and inversion symmetry are broken. The recently observed chirality-induced spin selectivity effect demonstrates that chiral materials break both symmetries. Thus a Josephson junction interface with the left-handed structure on one side of the junction and the right-handed structure on the other should exhibit a diode effect. Here, we report the electrical transport properties of right-handed/left-handed and right-handed/right-handed devices fabricated from single crystals of the structurally chiral superconductor Mo$_3$Al$_2$C. Fraunhofer-like magnetic diffraction patterns confirm the presence of Josephson effect in all but one of our devices. A magnetic field-induced superconducting diode effect is demonstrated in the right-handed/left-handed devices by a statistically significant difference in $I_{c+}$ and $I_{c-}$, with a maximum asymmetry of 5\%. The intrinsic superconducting diode effect is not observed in the right-handed/right-handed devices. We provide an explanation for the presence of the superconducting diode effect in the right-handed/left-handed devices.