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O: Fachverband Oberflächenphysik
O 32: Semiconductor Substrates
O 32.2: Vortrag
Dienstag, 27. März 2007, 16:00–16:15, H39
Interlayer interaction and electronic screening in multilayer graphene — •Karsten Horn1, Taisuke Ohta2, Aaron Bostwick2, Jessica McChesney3, Thomas Seyller4, and Eli Rotenberg2 — 1Fritz-Haber-Institut der MPG, Berlin — 2Advanced Light Source, LBL Berkeley — 3Montana State Universtiy, Bozeman, Montana — 4Inst. F.Physik der Kondens. Materie, Universität Erlangen-Nürnberg
Much recent attention has been given to the electronic structure of multilayer films of graphene, the honeycomb carbon sheet which is the building block of graphite, carbon nanotubes, C60 , and other mesoscopic forms of carbon. Recent progress in synthesizing or isolating multilayer graphene films has enabled access to their physical properties, and revealed many interesting transport phenomena, including an anomalous quantum Hall effect, ballistic electron transport at room temperature, micron-scale coherence length, and novel many-body couplings. The unusual transport properties of graphene originate from the effectively massless Dirac Fermion character of the carriers derived from graphene's valence bands, which exhibit a linear dispersion degenerate near the so-called Dirac point. We determine the shape of the π bands and their characteristic splitting, and the transition from a pure 2D to quasi-2D behavior for 1 to 4 layers of graphene by angle-resolved photoemission. By exploiting the sensitivity of the π bands to the electronic potential, we derive the layer-dependent carrier concentration, screening length and strength of interlayer interaction by comparison with tight binding calculations, yielding a comprehensive description of multilayer graphene's electronic structure.