Frankfurt 2014 – scientific programme

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HK: Fachverband Physik der Hadronen und Kerne

HK 42: Schwerionenkollisionen und QCD Phasen

HK 42.7: Talk

Thursday, March 20, 2014, 15:45–16:00, HZ 7

Lattice simulations of the interacting tight-binding model of graphene — •Dominik Smith¹ and Lorenz von Smekal^1,2 — ¹Technische Universität Darmstadt — ²Justus-Liebig-Universität Giessen

We present results of lattice simulations of the tight-binding model of graphene (carbon atoms arranged on a two-dimensional hexagonal lattice) using a realistic two-body interaction potential for the electronic quasi-particles in which screening of electromagnetic interactions is taken into account. We discuss the spontaneous breaking of the symmetry under exchange of the two triangular sub-lattices, which corresponds to a transition from a conducting to an insulating phase and which occurs when the effective fine structure constant of the theory crosses above a certain threshold. This transition posesses strong similarities to chiral symmetry breaking in relativistic field theory, due to the structure of the low-energy effective theory of graphene, which is a theory of strongly coupled massless Dirac particles. We present a prediction for the exact location of the transition and discuss the possibility of studying other phase transitions of the sytem, such as the topological Lifshitz transition which occurs at finite density in the pure tight-binding theory.

Gefördert von der DFG im Rahmen der Projekte SFB 634.