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

par Goldman, Nathan ;Anisimovas, Egidijus;Gerbier, Fabrice;Ohberg, P.;Spielman, I.B.;Juzeliunas, Gediminas
Référence New journal of physics, 15, page (30), 013025
Publication Publié, 2013

Article révisé par les pairs

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Résumé :

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. © IOP Publishing and Deutsche Physikalische Gesellschaft.