Anisotropic spin relaxation in graphene/hBN heterostructures

ORAL

Abstract

Measurements show a large and tunable anisotropy in the spin relaxation of hBN encapsulated bilayer graphene1,2, similar to what is observed in graphene/TMDC heterostructures3. Combining systematic first principles calculations for graphene/hBN heterostructures with a minimal tight-binding model, we extract spin-orbit coupling parameters of graphene in the µeV range. The extracted model parameters depend on (i) interlayer distances, (ii) stacking configurations, and (iii) an external electric field, resulting in a rich parameter space. Based on the Dyakonov-Perel formalism we calculate spin relaxation times for graphene, in the nanosecond range, in agreement with recent experimental measurements. A very important finding is that the spin relaxation anisotropy is maximum close to the charge neutrality point, decreasing with the doping level. In addition, we also show that the anisotropy can be tuned by means of an external electric field, via the precise control of the Rashba SOC.

1 Xu et al., PRL 121, 127703 (2018)
2 Leutenantsmeyer et al., PRL 121, 127702 (2018)
3 Cummings et al., PRL 119, 206601 (2017)

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Presenters

  • Klaus Zollner

    Institute for Theoretical Physics, University of Regensburg

Authors

  • Klaus Zollner

    Institute for Theoretical Physics, University of Regensburg

  • Martin Gmitra

    Institute of Physics, P. J. Safarik University in Kosice, P. J. Safarik University

  • Jaroslav Fabian

    University of Regensburg, Institute for Theoretical Physics, University of Regensburg