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arXiv · 2206.09478

Charge-to-spin conversion in twisted graphene/WSe$_2$ heterostructures

Seungjun Lee·D. J. P. de Sousa·Young-Kyun Kwon·Fernando de Juan·Zhendong Chi·Fèlix Casanova·Tony Low
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Abstract

We investigate the twist angle dependence of spin-orbit coupling (SOC) proximity effects and charge-to-spin conversion (CSC) in graphene/WSe$_2$ 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.

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Seungjun Lee, D. J. P. de Sousa, Young-Kyun Kwon, Fernando de Juan, Zhendong Chi, Fèlix Casanova, Tony Low. 2022-06-19. Charge-to-spin conversion in twisted graphene/WSe$_2$ heterostructures. https://doi.org/10.1103/physrevb.106.165420

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