Regensburg 2022 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 25: Poster 1
HL 25.21: Poster
Mittwoch, 7. September 2022, 18:00–20:00, P2
Twist angle dependent proximity induced spin-orbit coupling in graphene/WSe2/hBN heterostructures — •Tobias Rockinger1, Antony George2, Andrey Turchanin2, Ziyang Gan2, Kenji Watanabe3, Takashi Taniguchi3, Dieter Weiss1, and Jonathan Eroms1 — 1University of Regensburg, DE-93040 Regensburg, Germany — 2Friedrich-Schiller-Universität, DE-07743 Jena , Germany — 3NIMS, Tsukuba 305-0044, Japan
Recently, theoretical calculations predicted a strong dependence of the proximity-induced SOC on the twist angle between SLG and TMDCs [1]. To prove this, we fabricated SLG/WSe2/hBN heterostructures with well-defined twist angles between the SLG and WSe2 layers in two ways. For the first type, we exfoliated SLG and WSe2 which often break along zigzag or armchair edges [2]. This was used to align and estimate the rotation angles between the flakes (zigzag/armchair edges not distinguishable). For the other type of samples, we used CVD-grown WSe2 on anisotropically etched SLG to align and determine the twist angles exactly (zigzag/armchair edges distinguishable) [3]. Strong SOC causes weak anti-localization, which we used to determine the strength of the Rasbha type SOC (λR) and the valley-Zeeman type SOC (λVZ). We found that samples with an angle around 15∘ or 22∘ show a much stronger SOC in both cases, for λR as well as for λVZ, compared to samples, with twist angles around 0∘/30∘ or 11∘. This is in qualitative agreement with theoretical predictions [1]. [1]Y. Li and M. Koshino, Phys. Rev. B 99, (2019) 075438; [2]Y. Guo et al., ACS Nano 10, (2016) 8980; [3]P. Incze et al., Nano Res 3, (2010) 110