Gate-tunable spin-charge conversion and a role of spin-orbit interaction in graphene

TL;DR

This paper demonstrates gate-tunable spin-charge conversion in graphene, revealing the dominance of intrinsic spin-orbit interaction over Rashba effects, and highlights graphene's potential for spintronic applications despite its weak spin-orbit coupling.

Contribution

It provides experimental evidence of gate-controlled spin-charge conversion in graphene and clarifies the role of intrinsic versus Rashba spin-orbit interactions.

Findings

Inverse spin Hall effect is the main conversion mechanism.

Gate voltage modulates the spin-charge conversion signal.

Intrinsic spin-orbit interaction dominates over Rashba in graphene.

Abstract

The small spin-orbit interaction of carbon atoms in graphene promises a long spin diffusion length and potential to create a spin field-effect transistor. However, for this reason, graphene was largely overlooked as a possible spin-charge conversion material. We report electric gate tuning of the spin-charge conversion voltage signal in a single-layer graphene. Using spin pumping from yttrium iron garnet ferrimagnetic insulator and ionic liquid top gate we determined that the inverse spin Hall effect is the dominant spin-charge conversion mechanism in a single-layer graphene. From the gate dependence of the electromotive force we showed dominance of the intrinsic over Rashba spin-orbit interaction: a long-standing question in graphene research.