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Strongly anisotropic spin relaxation in graphene–transition metal dichalcogenide heterostructures at room temperature

Abstract

A large enhancement in the spin–orbit coupling of graphene has been predicted when interfacing it with semiconducting transition metal dichalcogenides. Signatures of such an enhancement have been reported, but the nature of the spin relaxation in these systems remains unknown. Here, we unambiguously demonstrate anisotropic spin dynamics in bilayer heterostructures comprising graphene and tungsten or molybdenum disulphide (WS2, MoS2). We observe that the spin lifetime varies over one order of magnitude depending on the spin orientation, being largest when the spins point out of the graphene plane. This indicates that the strong spin–valley coupling in the transition metal dichalcogenide is imprinted in the bilayer and felt by the propagating spins. These findings provide a rich platform to explore coupled spin–valley phenomena and offer novel spin manipulation strategies based on spin relaxation anisotropy in two-dimensional materials.

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Fig. 1: Proximity-induced SOC and measurement scheme.
Fig. 2: Spin relaxation anisotropy.
Fig. 3: Spin precession measurements under oblique magnetic fields.
Fig. 4: Spin lifetime anisotropy ratio, ζ

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Acknowledgements

We thank D. Torres for help in designing Fig. 1 and A. Cummings, S. Roche, J. Fabian and M. Timmermans for insightful discussions. This research was partially supported by the European Research Council under Grant Agreement 306652 SPINBOUND, by the European Union’s Horizon 2020 research and innovation programme under Grant Agreement 696656, by the Spanish Ministry of Economy and Competitiveness, MINECO (under Contracts MAT2016-75952-R and Severo Ochoa SEV-2013-0295), and by the CERCA Programme and the Secretariat for Universities and Research, Knowledge Department of the Generalitat de Catalunya 2014 SGR 56. J.F.S. acknowledges support from the MINECO Juan de la Cierva program and M.V.C. and F.B. from the MINECO Ramón y Cajal programme.

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L.A.B., J.F.S., W.S.T. and A.A. fabricated the devices and L.A.B., J.F.S. and W.S.T. made the measurements. F.B. helped with the device fabrication and M.V.C. with the device fabrication and measurements. L.A.B. and S.O.V. analysed the data and wrote the manuscript. All authors discussed the results and commented on the manuscript. S.O.V. supervised the work.

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Correspondence to L. Antonio Benítez or Sergio O. Valenzuela.

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Benítez, L.A., Sierra, J.F., Savero Torres, W. et al. Strongly anisotropic spin relaxation in graphene–transition metal dichalcogenide heterostructures at room temperature. Nature Phys 14, 303–308 (2018). https://doi.org/10.1038/s41567-017-0019-2

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