Specular-Andreev reflection and Andreev interference in an Ising superconductor junction

TL;DR

This paper investigates the unique Andreev reflection phenomena and interference effects in Ising superconductor junctions, revealing enhanced resilience and tunability due to exchange fields and spin-triplet pairing.

Contribution

It introduces the study of specular-Andreev reflection and Andreev interference in Ising superconductor junctions, highlighting the effects of exchange fields and spin-triplet pairing.

Findings

Specular-Andreev reflection occurs within a specific chemical potential range.

Interference can be modulated by exchange field orientation and phase difference.

Enhanced resilience of Andreev reflection against potential fluctuations.

Abstract

Being resilient to magnetic field, Ising superconductor serves as an exceptional platform for studying the interplay between superconductivity and magnetism. In this Letter, we first explore the transport properties of a two-terminal graphene-Ising superconductor junction where mirage gaps are induced in the superconductor by an exchange field due to magnetic proximity effect. We demonstrate that the chemical potential range of graphene supporting specular-Andreev reflection at the interface is between the two mirage gaps and about twice the Ising spin-orbit coupling strength. This enhances the resilience of observing specular-Andreev reflection against graphene potential fluctuations in experiments. We further study the Andreev interference effect based on a four-terminal junction of which two terminals consist of Ising superconductors in the presence of exchange fields. Due to the finite contribution from the spin-triplet pairing, the interference can be modulated by tuning the relative orientation of the exchange fields in addition to the traditional scheme by changing superconducting phase difference and the chemical potential of the normal region.