Perfect spin-triplet pairing in two-dimensional Ising superconductors purified by indirect excitons

TL;DR

This paper proposes a novel heterostructure approach to identify and control pairing symmetries in 2D superconductors, enabling the realization of topological superconductivity through magnetic field tuning.

Contribution

It introduces a method using van der Waals heterostructures with Coulomb tuning to distinguish and select spin-triplet pairing channels in 2D superconductors.

Findings

Coulomb attraction tuning affects indirect exciton insulator gaps.

In-plane magnetic fields can suppress non-triplet pairing channels.

The approach enables realization of topological superconductivity.

Abstract

Much research effort has been devoted to interfacial or two-dimensional (2D) superconductors, but the underlying pairing mechanisms and pairing symmetries are highly controversial in most cases. Here we propose an innovative approach to probe the pairing symmetry of 2D superconductors, based on a van der Waals heterostructure consisting of a prototypical 2D Ising superconductor coupled with a 2D hole gas through an insulating spacer. We first show that, by tuning the Coulomb attraction between the superconducting and hole layers, the gap of the corresponding indirect exciton insulators is tuned as well, resulting in contrasting manifestations of the distinct superconducting channels with spin-singlet (s-, extended s-, and d-wave) and spin-triplet (p- and f-wave) pairings. Strikingly, we find that the application of in-plane magnetic fields can suppress all other channels while selecting the spin-triplet p-wave channel to be the pure superconducting state, thus providing an ideal and practical platform for realizing highly desirable topological superconductivity. Such an approach can also be readily extended to other types of superconducting systems, offering unprecedented opportunities to probe the microscopic mechanisms of unconventional superconductivity.