Berlin 2018 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 13: Poster Session I
HL 13.9: Poster
Montag, 12. März 2018, 17:30–19:30, Poster B
Drag Experiments in Double Bilayer Graphene — Matthias Troiber1, Kenji Watanabe2, Takashi Taniguchi2, Dieter Weiss1, and •Jonathan Eroms1 — 1Institut für Experimentelle und Angewandte Physik, Universität Regensburg, Regensburg, Germany — 2National Institute for Materials Science, Tsukuba, Japan
We present experimental results on longitudinal and transverse drag in double bilayer graphene heterostructures. The graphene sheets were separated by a few nm thick hexagonal boron nitride (hBN) layer and were embedded into hBN using the van der Waals stacking technique. The density in both layers was controlled by a back and top gate, respectively. Drag measurements were performed at temperatures up to T=100 K and both at B=0 and in the quantum Hall regime. Similar to [1], at B=0 we observe a sign inversion of the drag voltages close to simultaneous charge neutrality in both layers. In the quantum Hall regime at elevated temperatures, we observe pronounced signatures in the drag signal at integer filling factors in either layer, despite the fact that in transport the QHE features are only barely visible. Also, at constant combined filling factor similar features appear in the drag signal. The results can be mostly interpreted within the Oppen-Simon-Stern theory [2], and we will discuss possible reasons for remaining discrepancies.
[1] J. I. A. Li, et al., Phys. Rev. Lett. 117, 046802 (2016).
[2] F. von Oppen, S. H. Simon, and A. Stern, Phys. Rev. Lett. 87, 106803 (2001).