Interaction-induced topological transition in spin-orbit coupled ultracold bosons

Recent experiments in ultracold atoms have reported the realization of quantum anomalous Hall phases in spin-orbit coupled systems.Motivated by such advances,we investigate spin-orbit coupled Bose-Bose mixtures in a two-dimensional square optical Raman lattice.Complete phase diagrams are obtained via a nonperturbative real-space bosonic dynamical mean-field theory.Various quantum phases are predicted,including Mott phases with z-ferromagnetic,xy-antiferromagnetic and vortex textures,and superfluid phases with the exotic spin orders,induced by the competition between the lattice hopping and spin-orbit coupling.To explain the underlying physics in the Mott regime,an efective Hamiltonian is derived based on second-order perturbation theory,where pseudospin order stems from the interplay of efective Dzyaloshinskii-Moriya superexchange and Heisenberg interactions.In the presence of the Zeeman field,the competition of strong interaction and Zeeman energy facilitates a topological phase,which is confirmed both by the nontrivial topological Bott index and spectral function with topological edge states.Our work indicates that spin-orbit coupling can induce rich non-Abelian topological physics in strongly correlated ultracold atomic systems.