Manipulation of Spin Transport in Graphene/Transition Metal Dichalcogenide Heterobilayers upon Twisting

TL;DR

This study shows how strain and twist-angle control spin-orbit coupling in graphene/TMD heterobilayers, significantly enhancing spin relaxation times and enabling tunable spin transport properties for advanced spintronic applications.

Contribution

It demonstrates that twist-angle and strain are effective tools to manipulate spin-orbit interactions in graphene heterostructures, providing insights into experimental variability and device optimization.

Findings

Spin relaxation times increase by two orders of magnitude at 30-degree twist-angle.

Strain and twist modify valley-Zeeman and Rashba spin-orbit couplings.

Potential to tune systems into an ideal Dirac-Rashba regime.

Abstract

Proximity effects are one of the pillars of exotic phenomena and technological applications of two dimensional materials. However, the interactions nature depends strongly on the materials involved, their crystalline symmetries, and interfacial properties. Here we used large-scale first-principle calculations to demonstrate that strain and twist-angle are efficient knobs to tailor the spin-orbit coupling in graphene transition metal dichalcogenide heterobilayers. We found that by choosing a twist-angle of 30 degrees, the spin relaxation times increase by two orders of magnitude, opening a path to improve these heterostructures spin transport capability. Moreover, we demonstrate that strain and twist angle will modify the relative values of valley-Zeeman and Rashba spin-orbit coupling, allowing to tune the system into an ideal Dirac-Rashba regime. These results enable us to envision an answer for the variability of spin-orbit coupling found in different experiments and have significant consequences for applications that depend on polycrystallinity, where grains form at different orientations.