Tailoring emergent spin phenomena in Dirac material heterostructures

Dirac materials such as graphene and topological insulators (TIs) are known to have unique electronic and spintronic properties. We combine graphene with TIs in van der Waals heterostructures to demonstrate the emergence of a strong proximity-induced spin-orbit coupling in graphene. By performing spin transport and precession measurements supported by ab initio simulations, we discover a strong tunability and suppression of the spin signal and spin lifetime due to the hybridization of graphene and TI electronic bands. The enhanced spin-orbit coupling strength is estimated to be nearly an order of magnitude higher than in pristine graphene. These findings in graphene-TI heterostructures could open interesting opportunities for exploring exotic physical phenomena and new device functionalities governed by topological proximity effects.Chalmers researchers acknowledge financial support from the European Union (EU) Horizon 2020 Research and Innovation Programme GrapheneCore2 contract number 785219 (Graphene Flagship), EU FLAG-ERA project (from Swedish Research Council VR no. 2015- 06813), Swedish Research Council VR project grants (no. 2016-03658), Graphene Center, and the AoA Nano program at Chalmers University of Technology. Catalan Institute of Nanoscience and Nanotechnology (ICN2) was supported by the Severo Ochoa program from Spanish Ministry of Economy and Competitiveness (MINECO; grant no. SEV-2013-0295) and funded by the Centres de Recerca de Catalunya Programme/Generalitat de Cataluña. S.R. acknowledges the Spanish MINECO and the European Regional Development Fund (project no. FIS2015- 67767-P MINECO/FEDER), and the Secretaría de Universidades e Investigación del Departamento de Economía y Conocimiento de la Generalitat de Cataluña (2014 SGR 58).Peer reviewe