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TT: Fachverband Tiefe Temperaturen

TT 48: CE: Metal-Insulator Transition 2

TT 48.5: Talk

Thursday, March 17, 2011, 11:30–11:45, HSZ 105

Metal-insulator transition in 2D disordered bipartite systems — •Elio König¹, Pavel Ostrovsky², Ivan Protopopov², and Alexander Mirlin^1,2 — ¹Institut für Theorie der Kondensierten Materie, Karlsruhe Institute of Technology (KIT), 76128 Karlsruhe, Germany — ²Institut für Nanotechnologie, Karlsruhe Institute of Technology (KIT), 76021 Karlsruhe, Germany

We predict the novel type of metal-insulator transition in 2D disordered systems with a bipartite structure. This in particular applies to graphene with vacancies and/or ripples and to topological insulators of unconventional symmetry. We use the σ-model description of these disordered systems and identify specific vortex-like excitations giving rise to the Berezinsky-Kosterlitz-Thouless-type transition. This results in appearence of the minimal metallic conductivity and insulating phase at sufficiently strong disorder. Our results are in agreement with available numerical simulations and motivate further theoretical and experimental studies of exotic disordered systems.