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arXiv · 1712.07282

Electrical spin manipulation in graphene nanostructures

R. Ortiz·N. A. García-Martínez·J. L. Lado·J. Fernández-Rossier
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Abstract

We propose a mechanism to drive singlet-triplet spin transitions electrically, in a wide class of graphene nanostructures that present pairs of in-gap zero modes, localized at opposite sublattices. Examples are rectangular nanographenes with short zigzag edges, armchair ribbon heterojunctions with topological in-gap states and graphene islands with sp$^3$ functionalization. The interplay between the hybridization of zero modes and Coulomb repulsion leads to symmetric exchange interaction that favors a singlet ground state. Application of an off-plane electric field to the graphene nanostructure generates an additional Rashba spin-orbit coupling, which results in antisymmetric exchange interaction that mixes $S=0$ and $S=1$ manifolds. We show that modulation in time of either the off-plane electric field or the applied magnetic field permits to perform electrically driven spin resonance in a system with very long spin relaxation times.

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R. Ortiz, N. A. García-Martínez, J. L. Lado, J. Fernández-Rossier. 2017-12-20. Electrical spin manipulation in graphene nanostructures. https://doi.org/10.1103/physrevb.97.195425

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