We investigate the twist angle dependence of spin-orbit coupling (SOC) proximity effects and charge-to-spin conversion (CSC) in graphene/WSe2 heterostructures from first principles. The CSC is shown to strongly depend on the twist angle, with both the spin Hall and standard Rashba-Edelstein efficiencies optimized at or near 30{\deg} twisting. Symmetry breaking due to twisting also gives rise to an unconventional Rashba-Edelstein effect, with electrically generated non-equilibrium spin densities possessing spins collinear to the applied electric field. We further discuss how the carrier doping concentration and band broadening control the crossover between the Fermi-sea and -surface spin response, which reconciles the seemingly disparate experimental observations of different CSC phenomena.
@article{arxiv.2206.09478,
title = {Charge-to-spin conversion in twisted graphene/WSe$_2$ heterostructures},
author = {Seungjun Lee and D. J. P. de Sousa and Young-Kyun Kwon and Fernando de Juan and Zhendong Chi and Fèlix Casanova and Tony Low},
journal= {arXiv preprint arXiv:2206.09478},
year = {2022}
}
Comments
5 pages, 4 figures, Supplementary Information (13 pages, 7 figures)