Berlin 2024 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 5: 2D Materials and their Heterostructures II: Graphene and Graphene Containing Heterostructures
DS 5.2: Vortrag
Dienstag, 19. März 2024, 09:45–10:00, A 053
Twist angle dependent proximity induced spin-orbit-coupling in graphene/NbSe2 heterostructures — •Thomas Naimer1, Martin Gmitra2, and Jaroslav Fabian1 — 1Institute for Theoretical Physics, University of Regensburg, 93040 Regensburg, Germany — 2Pavol Jozef Safarik University in Kosice, 04001 Kosice, Slovakia
We investigate the effect of the twist angle on the proximity spin-orbit coupling (SOC) in graphene/niobium diselenide (Gr/NbSe2) heterostructures from first principles. The low energy Dirac cones of several different commensurate twisted supercells are fitted to a model Hamiltonian, allowing us to analyze the twist-angle dependency of the SOC in detail. This reveals the possibility to triple the Rashba SOC, when going from 0° to 30° twist angle. Furthermore, at a critical twist angle of 23° the in-plane spin structure acquires a significant radial component, enabling collinear charge-to-spin conversion. Analyzing the Dirac cone with respect to allowed Umklapp processes and orbital decomposition shines light on the observed twist angle dependencies. In addition, we evaluate the potential for (collinear and perpendicular) charge-to-spin conversion in such heterostructures within linear response theory. This work was funded by the Elite Network of Bavaria, the Deutsche Forschungsgemeinschaft (DFG), SFB 1277, SPP 2244 and by the European Union Horizon 2020 Research and Innovation Program under contract number 881603 (Graphene Flagship). M.G. acknowledges VEGA 1/0105/20.
Keywords: graphene; proximity effect; spin-orbit coupling; twist angle