SKM 2021 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 3: Poster Session I
HL 3.26: Poster
Monday, September 27, 2021, 10:00–13:00, P
Quantum anomalous Hall effect in Bernal-stacked bilayer graphene — Fabian Geisenhof1, Felix Winterer1, Anna Seiler2, Jakob Lenz1, Tianyi Xu3, Fan Zhang3 und •Thomas Weitz2 — 1Department of Physics, Ludwig-Maximilians-Universität München, Germany — 2Department of Physics, University of Texas at Dallas, USA — 31st Physical Institute, University of Göttingen, Germany
The anomalous quantum Hall effect is a peculiar state of matter that has been observed in only very few materials systems including artificially engineered Moiré heterostructures [1]. However, the special bandstructure of naturally occurring bilayer graphene, has also been predicted to host an interaction-driven quantum anomalous Hall insulating phase at zero magnetic field [2], which has escaped previous experimental observation. Here, based on advanced sample design of near-field imaging, suspension and dual-gating, we show clear signatures of this quantum anomalous Hall insulating phase in ultra-clean bilayer graphene [3]. Besides the simplicity, diversity, and robustness of the system, the quantum anomalous Hall phase is also distinct from previously observed ones, since it is the first phase that does not only exhibit quantized charge Hall conductance at zero magnetic field, but also spin, valley and spin-valley anomalous quantum Hall effects as well as out-of-plane ferroelectricity.
[1] A.L. Sharpe, et al. Science 365, 605 (2019); M. Serlin, et al. Science 367, 900 (2020),
[2] F. Zhang Synthetic Metals 210, 9 (2015)
[3] F. R. Geisenhof, et al. arXiv:2107.06915 (2021)