Chiral topological superfluids in the attractive Haldane-Hubbard model with opposite Zeeman energy at two sublattice sites
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Ultracold atoms in an optical lattice provide a platform for the realization of the topological superfluid. Motivated by the recent cold atom realization of the topological Haldane model [G. Jotzu, M. Messer, R. Desbuquois, M. Lebrat, Th. Uehlinger, D. Greif, T. Esslinger, Nature 515, 237 (2014)], in this paper we propose an alternative way to realize chiral topological superfluids with Chern number 𝒞 = 1 and 2 by considering attractive Haldane-Hubbard model with the site-dependent Zeeman field. The topological superfluids support the robust chiral edge modes, and the one-half of flux quantum-π flux in 𝒞 = 1 topological superfluid traps a pair of Majorana zero modes different from the case in the spinless p x ± i p y topological superfluid due to the extra freedom of A-B sublattices. In addition, we discuss the superfluid stability and calculate Kosterlitz-Thouless transition temperature by random-phase-approximation approach.