The Andreev-Ising-Josephson Diode

TL;DR

This paper investigates spin-split Andreev bound states in Ising superconductor Josephson junctions, revealing tunable nonreciprocal supercurrents and diode effects with high efficiency, applicable in 2D heterostructures.

Contribution

It demonstrates the emergence of spin-split Andreev states and tunable diode effects in Ising superconductor Josephson junctions with misoriented in-plane fields.

Findings

Spin-split Andreev bound states due to field misorientation.

Non-sinusoidal supercurrent-phase relations observed.

High diode efficiency (~40%) tunable by exchange fields.

Abstract

The transition-metal dichalcogenides featuring Ising spin-orbit coupling in so-called Ising superconductors offer a unique system to study the interplay of singlet and triplet superconductivity. The presence of high critical fields, spectral properties such as the mirage gap, and field-tunable charge and spin currents in Ising-superconductor Josephson junctions are some of the important features. In this work, we study Ising-superconductor Josephson junction with a transparent interface and show that Andreev bound states are spin-split due to a relative misorientation of in-plane fields in the superconducting contacts. Correspondingly, supercurrent-phase relations display a strongly non-sinusoidal behavior. Introducing additional spin-polarized channels with low transmission results in a nonreciprocal current-phase relation with a diode effect that can be tuned by the in-plane exchange fields. The diode efficiency reaches high values of the order of 40% and is not sensitive to disorder in the junction. Such structures can be realized in van-der-Waals heterostructures of two dimensional superconductors and magnets.