We report the observation of current-induced spin polarization, the Rashba-Edelstein effect (REE), and its Onsager reciprocal phenomenon, the spin galvanic effect (SGE), in a few-layer graphene/2H-TaS2 heterostructure at room temperature. Spin-sensitive electrical measurements unveil full spin-polarization reversal by an applied gate voltage. The observed gate-tunable charge-to-spin conversion is explained by the ideal work function mismatch between 2H-TaS2 and graphene, which allows strong interface-induced Bychkov-Rashba interaction with a spin-gap reaching 70 meV, while keeping the Dirac nature of the spectrum intact across electron and hole sectors. The reversible electrical generation and control of the nonequilibrium spin polarization vector, not previously observed in a nonmagnetic material, are elegant manifestations of emergent 2D Dirac fermions with robust spin-helical structure. Our experimental findings, supported by first-principles relativistic electronic structure and transport calculations, demonstrate a route to design low-power spin-logic circuits from layered materials.
@article{arxiv.1906.10702,
title = {Gate-Tunable Reversible Rashba-Edelstein Effect in a Few-Layer Graphene/2H-TaS2 Heterostructure at Room Temperature},
author = {Lijun Li and Jin Zhang and Gyuho Myeong and Wongil Shin and Hongsik Lim and Boram Kim and Seungho Kim and Taehyeok Jin and Stuart A. Cavill and Beom Seo Kim and Changyoung Kim and Johannes Lischner and Aires Ferreira and Sungjae Cho},
journal= {arXiv preprint arXiv:1906.10702},
year = {2020}
}
Comments
Main text (24 pages, 4 figures) + supplementary material (29 pages, 15 figures). Experimental data for Onsager-reciprocal effect (SGE) added. Title, abstract, main text, references and SM updated