Twist Angle Controlled Collinear Edelstein Effect in van der Waals Heterostructures

TL;DR

This paper predicts that twist-angle control in van der Waals heterostructures enables tunable spin-charge transport phenomena, including a collinear Edelstein effect at specific angles, with potential for room temperature spintronic applications.

Contribution

It introduces the concept of twist-angle tuning in van der Waals heterostructures to control spin responses, highlighting the robustness and potential for electrical detection of the collinear Edelstein effect.

Findings

Room temperature spin-current responses in graphene/TMD bilayers.

Critical twist angle (~14°) for collinear spin response.

Robustness of the effect against twist-angle disorder.

Abstract

The generation of spatially homogeneous spin polarization by application of electric current is a fundamental manifestation of symmetry-breaking spin--orbit coupling (SOC) in solid-state systems, which underpins a wide range of spintronic applications. Here, we show theoretically that twisted van der Waals heterostructures with proximity-induced SOC are candidates par excellence to realize exotic spin-charge transport phenomena due to their highly tunable momentum-space spin textures. Specifically, we predict that graphene/group-VI dichalcogenide bilayers support room temperature spin--current responses that can be manipulated via twist-angle control. For critical twist angles, the non-equilibrium spin density is pinned parallel to the applied current. This effect is robust against twist-angle disorder, with graphene/$\text{WSe}_{2}$ possessing a critical angle (purely collinear response) of $\theta_{c} \simeq 14^{\circ}$. A simple electrical detection scheme to isolate the collinear Edelstein effect is proposed.