Gate-tunable Spin-Galvanic Effect in Graphene Topological insulator van der Waals Heterostructures at Room Temperature

TL;DR

This paper demonstrates a room-temperature, gate-tunable spin-galvanic effect in graphene-topological insulator heterostructures, enabling efficient spin-charge conversion for spintronic applications.

Contribution

It introduces a novel heterostructure system with electrically controllable spin-galvanic effects at room temperature, advancing spin-orbit technology.

Findings

Gate voltage controls spin-galvanic amplitude and sign.

Robust spin-charge conversion demonstrated across device geometries.

Potential for low-power, all-electrical spintronic devices.

Abstract

Unique electronic spin textures in topological states of matter are promising for emerging spin-orbit driven memory and logic technologies. However, there are several challenges related to the enhancement of their performance, electrical gate-tunability, interference from trivial bulk states, and heterostructure interfaces. We address these challenges by integrating two-dimensional graphene with a three-dimensional topological insulator (TI) in van der Waals heterostructures to take advantage of their remarkable spintronic properties and engineer proximity-induced spin-charge conversion phenomena. In these heterostructures, we experimentally demonstrate a gate tunable spin-galvanic effect (SGE) at room temperature, allowing for efficient conversion of a nonequilibrium spin polarization into a transverse charge current. Systematic measurements of SGE in various device geometries via a spin switch, spin precession, and magnetization rotation experiments establish the robustness of spin-charge conversion in the Gr-TI heterostructures. Importantly, using a gate voltage, we reveal a strong electric field tunability of both amplitude and sign of the spin-galvanic signal. These findings provide an efficient route for realizing all-electrical and gate-tunable spin-orbit technology using TIs and graphene in heterostructures, which can enhance the performance and reduce power dissipation in spintronic circuits.