Giant and gate-tunable spin-galvanic effect in graphene-topological insulator van der Waals heterostructures at room temperature

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 graphene [1] with a 3D topological insulator (TI) in a van der Waals heterostructure [2] to take advantage of their remarkable spintronic properties and engineer strong proximity-induced spin-charge conversion phenomena. In these heterostructures, we experimentally demonstrate a giant spin-galvanic effect at room temperature due to an efficient conversion of a nonequilibrium spin polarization into a transverse charge current [3]. Importantly, we show a strong gate-tunability of the spin-galvanic signal, tracing its origin to the proximity-induced Rashba-Edelstein effect. These findings open interesting opportunities for exploring exotic physical phenomena and new device functionalities governed by topological proximity effects.

1. Khokhriakov, et al., arXiv:1905.04151 (2019).
2. Khokhriakov, et al., Science Advances, 4, 9, eaat9349 (2018).
3. Khokhriakov, et al., arXiv:1910.06760 (2019).