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

TitleMeasuring topology in a laser-coupled honeycomb lattice: from Chern insulators to topological semi-metals
Publication TypeJournal Article
Year of Publication2013
AuthorsN. Goldman, E. Anisimovas, F. Gerbier, P. Oehberg, I. B. Spielman, and G. Juzeliūnas
JournalNew J. Phys.

Ultracold fermions trapped in a honeycomb optical lattice constitute a versatile setup to experimentally realize the Haldane model (1988 Phys. Rev. Lett. 61 2015). 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 paper, 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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