Regensburg 2010 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 14: TR: Graphene 2
TT 14.6: Vortrag
Dienstag, 23. März 2010, 10:45–11:00, H21
How Graphene-like is Epitaxial Graphene? Quantum Oscillations and Quantum Hall Effect — •Johannes Jobst1, Daniel Waldmann1, Florian Speck2, Roland Hirner2, Duncan K. Maude3, Thomas Seyller2, and Heiko B. Weber1 — 1Lehrstuhl für Angewandte Physik, Universität Erlangen-Nürnberg, 91058 Erlangen, Germany — 2Lehrstuhl für Technische Physik, Universität Erlangen-Nürnberg, 91058 Erlangen, Germany — 3Laboratoire des Champs Magnétiques Intenses, 25 Avenue des Martyrs, 38042 Grenoble, France
We report on the transport properties -- in particular charge carrier density, mobility, conductivity and magnetoconductance -- of high-quality single-layer graphene. Graphene was epitaxially grown on the silicon terminated face of a semi-insulating 6H silicon carbide substrate and then patterned into devices of different geometry and size. Large samples as well as submicrometer-sized Hall bars which are entirely lying on atomically flat substrate terraces yield similar transport properties confirming the uniformity of the epitaxial process. In high magnetic fields Shubnikov-de Haas oscillations with the distinct Landau level spectrum of single-layer graphene are clearly visible in samples with different charge carrier densities. When gated close to the Dirac point, the mobility increases substantially, and the graphene-like quantum Hall effect occurs. This proves that epitaxial graphene is ruled by the same pseudo-relativistic physics observed previously in exfoliated graphene.