Dresden 2014 – scientific programme

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O: Fachverband Oberflächenphysik

O 44: Low-Dimensional Systems: 2D - Theory (TT jointly with O)

O 44.4: Talk

Wednesday, April 2, 2014, 10:15–10:30, BEY 81

Correlated spinless fermions on the honeycomb lattice — •Martin Hohenadler¹ and Maria Daghofer² — ¹University of Würzburg, Germany — ²IFW Dresden, Germany

We study the phase diagram of spinless fermions on the honeycomb lattice with nearest– (V₁) and next-nearest neighbour repulsion (V₂) using numerical methods. At the mean-field level, this model has been shown to describe an interaction-generated quantum anomalous Hall (QAH) phase with nonzero Chern index [Raghu et al., PRL 100, 156401 (2008)]. Our exact results reveal that this phase is completely suppressed by quantum fluctuations. However, for small V₂, we find that V₂ enhances bond order correlations that resemble the mean-field bond order in the QAH phase. This weak-coupling tendency toward a QAH state suggests that the phase may be realized in other models.