Van der Waals heterostructures with spin-orbit coupling

TL;DR

This review explores van der Waals heterostructures with strong spin-orbit coupling, highlighting their unique electronic and superconducting properties, and discusses models, transport effects, and tunable superconductivity in these layered systems.

Contribution

It provides a comprehensive overview of theoretical models and experimental insights into vdW heterostructures with spin-orbit coupling, including novel transport phenomena and superconducting states.

Findings

Enhanced spin-dependent transport in topological insulator-graphene systems

Realization of odd-frequency superconducting correlations in layered heterostructures

Tunable proximity-induced superconductivity in twisted graphene-NbSe2 bilayers

Abstract

In this article we review recent work on van der Waals (vdW) systems in which at least one of the components has strong spin-orbit coupling. We focus on a selection of vdW heterostructures to exemplify the type of interesting electronic properties that can arise in these systems. We first present a general effective model to describe the low energy electronic degrees of freedom in these systems. We apply the model to study the case of (vdW) systems formed by a graphene sheet and a topological insulator. We discuss the electronic transport properties of such systems and show how they exhibit much stronger spin-dependent transport effects than isolated topological insulators. We then consider vdW systems in which the layer with strong spin-orbit coupling is a monolayer transition metal dichalcogenide (TMD) and briefly discuss graphene-TMD systems. In the second part of the article we discuss the case in which the vdW system includes a superconducting layer in addition to the layer with strong spin-orbit coupling. We show in detail how these systems can be designed to realize odd-frequency superconducting pair correlations. Finally, we discuss twisted graphene-NbSe2 bilayer systems as an example in which the strength of the proximity-induced superconducting pairing in the normal layer, and its Ising character, can be tuned via the relative twist angle between the two layers forming the heterostructure.