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arXiv · 1209.1126

Measuring topology in a laser-coupled honeycomb lattice: From Chern insulators to topological semi-metals

N. Goldman·E. Anisimovas·F. Gerbier·P. Ohberg·I. B. Spielman·G. Juzeliunas
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Abstract

Ultracold fermions trapped in a honeycomb optical lattice constitute a versatile setup to experimentally realize the Haldane model [Phys. Rev. Lett. 61, 2015 (1988)]. In this system, a non-uniform synthetic magnetic flux can be engineered through laser-induced methods, explicitly breaking time-reversal symmetry. This potentially opens a bulk gap in the energy spectrum, which is associated with a non-trivial topological order, i.e., a non-zero Chern number. In this work, we consider the possibility of producing and identifying such a robust Chern insulator in the laser-coupled honeycomb lattice. We explore a large parameter space spanned by experimentally controllable parameters and obtain a variety of phase diagrams, clearly identifying the accessible topologically non-trivial regimes. We discuss the signatures of Chern insulators in cold-atom systems, considering available detection methods. We also highlight the existence of topological semi-metals in this system, which are gapless phases characterized by non-zero winding numbers, not present in Haldane's original model.

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N. Goldman, E. Anisimovas, F. Gerbier, P. Ohberg, I. B. Spielman, G. Juzeliunas. 2012-09-05. Measuring topology in a laser-coupled honeycomb lattice: From Chern insulators to topological semi-metals. https://doi.org/10.1088/1367-2630%2F15%2F1%2F013025

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