Eur. Phys. J. B (2015) 88: 255
https://doi.org/10.1140/epjb/e2015-60412-y

Regular Article

Chiral topological superfluids in the attractive Haldane-Hubbard model with opposite Zeeman energy at two sublattice sites

¹ School of Science, Xi’an Technological University, Xi’an 710032, P.R. China
² Department of Physics, Beijing Normal University, Beijing 100875, P.R. China

^a e-mail: wuyajie@xatu.edu.cn

Received: 23 May 2015
Received in final form: 23 August 2015
Published online: 12 October 2015

Abstract

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 ± ip_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.