Berlin 2012 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 22: Graphene: Structure and Theory II

HL 22.3: Talk

Monday, March 26, 2012, 17:45–18:00, EW 201

Electronic Structure of Graphene Twist Flakes — •Karla Türschmann, Wolfgang Landgraf, Sam Shallcross, and Oleg Pankratov — Theoretische Festkörperphysik, Universität Erlangen, Staudtstr. 7B2, 91058 Erlangen

The chemical exfoliation of graphene, that is the reduction of a highly ordered graphite crystal to single and multilayer graphene flakes via a wet chemical route, represents one of the most promising techniques for the mass production of high quality graphene. The bilayer flakes most probably consist of mutually rotated graphene layers, and in this work we describe the electronic properties of such systems. We use the tight-binding method in conjunction with Lanczos diagonalisation allowing us to access the required very large system sizes. For large twist angles we find an electronic decoupling of the flake layers, whereas for small angles we find a localisation of low energy quantum states associated with the moire pattern of AA and AB stacked regions of the twist flake.