SKM 2021 – wissenschaftliches Programm
CPP 1.6: Vortrag
Montag, 27. September 2021, 12:30–12:45, H3
Twist angle dependent proximity induced spin-orbit coupling in graphene/transition-metal dichalcogenide heterostructures — •Thomas Naimer1, Klaus Zollner1, Martin Gmitra2, and Jaroslav Fabian1 — 1Institute for Theoretical Physics, University of Regensburg, 93040 Regensburg, Germany — 2Institute of Physics, P. J. Šafárik University in Košice, 04001 Košice, Slovakia
We investigate proximity-induced spin-orbit coupling (SOC) in graphene on the four transition-metal dichalcogenides (TMDCs) MoS2, WS2, MoSe2 and WSe2 from first principles. By using different supercells of graphene/TMDC heterostructures we provide systematic insight on the effect of twist angles on the low energy Dirac spectrum. We find that the exact position of the Dirac cone within the TMDC band gap depends linearly on the biaxial strain applied to the graphene. From this relation we extrapolate the zero-strain band offset and correct the band offsets of all calculations by employing a transverse electric field across the heterostructure. The corrected results reveal massive twist angle tunability of both the magnitude and flavor of proximity induced SOC: We observe a peak in SOC at approximately 19∘ twist angle and vanishing SOC at 30∘. This work was supported by ENB "Topologische Isolatoren" and SFB 1277.