Mercredi 12 février 2020 à 14h00, Marius Costache (Catalan Institute of Nanoscience and Nanotechnology (ICN2), Barcelona, Spain) donnera un séminaire sur "Spintronics with 2D-materials"
Abstract :
Two-dimensional (2D) materials, exhibiting both exotic electronic band-structures and spin textures, provide a unique platform for spintronics and magnetism. For example, graphene provides excellent spin transport ; transition metal dichalcogenides (TMD) provide strong spin-orbit coupling and valley-selective transitions and topological insulators have their spin locked to their momentum. Among these, graphene has taken center stage. Due to its weak spin-orbit coupling the spin currents in graphene flow over very long distances (tens of micrometers) [1]. However, this also means that the spin currents are hard to manipulate, a drawback for technological applications.
There are at least two routes for manipulation of spin currents. One way is by engineering an energy bandgap into the graphene that allows to turn the flow of electrons on and off. We have recently reported the fabrication of graphene nanoribbons that show a field-effect transistor with a large on-off ratio and a high device yield [2].
The other way is by stacking a TMD layer onto graphene which imparts a proximity spin-orbit coupling, allowing for spin-charge conversion and electrical manipulation of spin. We recently demonstrated that proximity effect results in anisotropic spin dynamics on MoSe2/graphene and WS2/graphene spin valves [3]. Subsequently, using these heterostructures we demonstrated spin-charge conversion by spin Hall and spin galvanic effects [4].
[1] M. Gebeyehu et al., 2D Materials, 6, 3, 034003 (2019).
[2] C. Moreno et al., Science, 360, 199 (2018).
[3] A. Benítez et al., Nature Physics, 14, 303 (2018).
[4] A. Benítez et al., Nature Materials, (2020).
