Berlin 2015 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 19: Transport: Graphene (joint session TT, CPP, DS, DY, HL, MA, O)

CPP 19.3: Talk

Tuesday, March 17, 2015, 10:00–10:15, A 053

Aharonov-Bohm effect in a graphene ring encapsulated in hexagonal boron nitride — •Jan Dauber^1,2, Martin Oellers¹, Alexander Epping^1,2, Kenji Watanabe³, Takashi Taniguchi³, Fabian Hassler⁴, and Christoph Stampfer^1,2 — 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.