Regensburg 2016 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 12: Graphene: Transport
(Joint session of DS, DY, HL, MA, O and TT organized by HL)
TT 12.6: Vortrag
Montag, 7. März 2016, 16:45–17:00, H17
Magnetotransport in graphene antidot arrays: semiclassics and moiré lattices — •Andreas Sandner1, Tobias Preis1, Christian Schell1, Paula Giudici1, Kenji Watanabe2, Takashi Taniguchi2, Dieter Weiss1, and Jonathan Eroms1 — 1Institut für Experimentelle und Angewandte Physik, Universität Regensburg, Germany — 2NIMS, 1-1 Namiki, Tsukuba, Japan
Embedding graphene into a heterostructure with hexagonal boron nitride (hBN) on both sides was shown to be an efficient way of achieving a high bulk mobility. However, nanopatterning graphene can add extra damage and drastically degrade the intrinsic properties by edge disorder. But graphene encapsulated between hBN is protected during a top-down fabrication procedure. In this way, we can prepare graphene-based antidot lattices where the high mobility is preserved.
We performed magnetotransport experiments in monolayer-graphene antidot lattices with lattice periods down to 50 nm. We observe pronounced commensurability features in ρxx stemming from ballistic orbits around one or several antidots. Due to the short lattice period in our samples, we can explore the boundary between the semiclassical and the quantum transport regime, as the Fermi wavelength of the electrons approaches the smallest length scale of the artificial potential.
Additionally, we study the interplay between a moiré and the imposed antidot superlattice potential in several of our samples. There is a gradual suppression of the classical commensurability features by approaching the satellite Dirac points of the moiré potential.