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HL: Fachverband Halbleiterphysik

HL 78: Transport: Graphene 1 (jointly with TT, MA, DY, DS, O)

HL 78.5: Vortrag

Donnerstag, 29. März 2012, 10:30–10:45, BH 334

The Hubbard model on the bilayer honeycomb lattice with Bernal stacking — •Thomas C. Lang¹, Stefan Übelacker¹, Zi Yang Meng², Michael Scherer¹, Carsten Honerkamp¹, Alejandro Muramatsu³, Fakher F. Assaad⁴, and Stefan Wessel¹ — ¹RWTH Aachen, Aachen, Germany — ²Louisiana State University, Baton Rouge, USA — ³Universität Stuttgart, Stuttgart, Germany — ⁴Universität Würzburg, Würzburg, Germany

Using a combination of quantum Monte Carlo, the functional renormalization group and mean-field theory we study the Hubbard model on the bilayer honeycomb as a model for interacting electrons on bilayer graphene. The free bands consisting of two Fermi points with quadratic dispersions lead to a finite density of states, which triggers the antiferromagnetic instability and spontaneously breaks sublattice and spin rotational symmetry once a local Coulomb repulsion is introduced. We show that the antiferromagnetic instability is insensitive to the inclusion of extended Coulomb interactions and discuss effects on the sublattice magnetization and of finite size systems in numerical approaches.