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Measuring Topology in a Laser-Coupled Honeycomb Lattice: From Chern Insulators to Topological Semi-Metals



Ian B. Spielman, Nathan Goldman, Egidijus Anisimovas, Fabrice Gerbier, Patrick Ohberg, Gediminas Juzeliunas


Ultracold fermions trapped in a honeycomb optical lattice constitute a versatile setup to experimentally realize the Haldane model. 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.
New Journal of Physics


artificial gauge fields, chern numbers, time-of-flight


Spielman, I. , , N. , Anisimovas, E. , Gerbier, F. , Ohberg, P. and Juzeliunas, G. (2013), Measuring Topology in a Laser-Coupled Honeycomb Lattice: From Chern Insulators to Topological Semi-Metals, New Journal of Physics, [online], (Accessed April 22, 2024)
Created January 14, 2013, Updated November 10, 2018