Unconventional superconductivity in bilayer transition metal dichalcogenides

TL;DR

This paper explores unconventional superconductivity in bilayer transition metal dichalcogenides, highlighting how their unique spin-valley-layer coupling and centrosymmetric structure lead to diverse pairing states and potential inhomogeneous phases under magnetic fields.

Contribution

It predicts new superconducting phases, including intra-layer, inter-layer singlet, and inter-layer triplet pairings, and suggests the existence of FFLO states in bilayer TMDs under magnetic fields.

Findings

Rich phase diagram with multiple pairing symmetries

Prediction of FFLO state in bilayer TMDs

Discussion of experimental signatures

Abstract

Bilayer transition metal dichalcogenides (TMDs) belong to a class of materials with two unique features, the coupled spin-valley-layer degrees of freedom and the crystal structure that is globally centrosymmetric but locally non-centrosymmetric. In this work, we will show that the combination of these two features can lead to a rich phase diagram for unconventional superconductivity, including intra-layer and inter-layer singlet pairings and inter-layer triplet pairings, in bilayer superconducting TMDs. In particular, we predict that the inhomogeneous Fulde-Ferrell-Larkin-Ovchinnikov state can exist in bilayer TMDs under an in-plane magnetic field. We also discuss the experimental relevance of our results and possible experimental signatures.