Dresden 2009 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 8: Postersession Transport: Graphene and Carbon Nanotubes

TT 8.7: Poster

Montag, 23. März 2009, 13:00–16:45, P1B

Disorder effects in graphene: A local distribution approach — •Jens Schleede, Gerald Schubert, and Holger Fehske — Institute for Physics, Ernst-Moritz-Arndt Universität Greifswald, Germany

We present a study of different models of local disorder in mono- and bilayer graphene and graphene nanoribbons. In particular, we investigate the Anderson model on a two-dimensional honeycomb lattice and determine the probability distribution of the local density of states using a highly efficient kernel polynomial method. Supplemented by a careful finite-size scaling analysis, this quantity allows for distinguishing extended from localised states. Our findings are corroborated by the evaluation of the time evolution of an initially localised wave packet, which is based on Chebyshev expansion technique. While our results for the 2D infinite systems indicate complete localisation for arbitrary weak Anderson disorder, the finite system sizes of graphene strips (nanoribbons) induce another length scale to the problem. So despite the localisation on large length scales, finite 2D devices may show metallic behaviour for weak disorder. Moreover we show that the ground state properties of graphene are largely affected by the geometric pattern and disorder at their edges.