Regensburg 2007 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 37: Symposium Graphene
HL 37.5: Hauptvortrag
Donnerstag, 29. März 2007, 12:00–12:30, H15
The structure of suspended graphene membranes — •J. C. Meyer1, A. K. Geim2, M. I. Katsnelson3, K. S. Novoselov2, T. Booth2, D. Obergfell4, S. Roth4, C. Girit1, A. Kis1, and A. Zettl1 — 1Materials Science Dept. Lawrence Berkeley National Laboratory, and Physics Dept. University of California, Berkeley, USA — 2Manchester Centre for Mesoscience and Nanotechnology, University of Manchester, UK — 3Institute for Molecules and Materials, University of Nijmegen, Netherlands — 4Max Planck Institute for solid state research, Stuttgart, Germany
Graphene is a monolayer of carbon atoms that can be viewed as an individual atomic plane extracted from graphite. The charge carriers mimic massless Dirac fermions, and this peculiar electronic structure has been at the focus of the recent interest in this material. But already the structure of graphene is intriguing. The notion of an isolated graphite plane implies a two-dimensional crystal, which can not exist in a free state according to theory. We have now prepared prepared freely suspended graphene monolayers that are not confined in the third dimension, and are attached only at the edges. We investigate structural or mechanical effects of these atomically thin membranes by transmission electron microscopy. Indeed, we observe structural effects that are not found in bulk crystals but are unique to the 2D membrane. The membranes do not remain flat but exhibit random variations in the surface normal of several degrees. This is in qualitative agreement with theoretical predictions for a 2D membrane in a 3D space, however, a rigid theoretical treatment for this particular system is still needed.