Berlin 2015 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 29: Transport: Graphene (TT with CPP/DS/DY/HL/O)
HL 29.3: Vortrag
Dienstag, 17. März 2015, 10:00–10:15, A 053
Aharonov-Bohm effect in a graphene ring encapsulated in hexagonal boron nitride — •Jan Dauber1,2, Martin Oellers1, Alexander Epping1,2, Kenji Watanabe3, Takashi Taniguchi3, Fabian Hassler4, and Christoph Stampfer1,2 — 1JARA-FIT and 2nd Institute of Physics, RWTH Aachen University, Aachen, Germany — 2Peter Grünberg Institute (PGI-9), Forschungszentrum Jülich, Jülich, Germany — 3National Institute for Materials Science, 1-1 Namiki, Tsukuba, Japan — 4JARA-Institute for Quantum Information at RWTH Aachen University, Aachen, Germany
Recent developments in the van der Waals assembly of heterostructures of two-dimensional materials enable the fabrication of graphene on substrate with very high quality. Outstanding charge carrier mobility and mean free path have been reported for micrometer sized samples of graphene encapsulated in hexagonal boron nitride (hBN). These unique electronic properties offer opportunities for the observation of rich mesoscopic transport phenomena in sub-micron sized graphene-hBN devices. Here, we present low-temperature magneto-transport measurements on a high mobility graphene ring encapsulated in hexagonal boron nitride. We observe the co-existence of weak localization, Aharonov-Bohm (AB) oscillations and universal conductance fluctuations. We investigate the periodicity of the AB oscillations as a function of charge carrier density and find clear evidence of the AB effect even at very low carrier densities. Finally, we report on the investigation of the AB oscillations in the cross over regime of emerging quantum Hall effect at reasonable magnetic fields.