Luo, X (reprint author), Fudan Univ, Dept Phys, State Key Lab Surface Phys & Collaborat Innovat, Ctr Field Theory & Particle Phys,Ctr Adv Microstr, Shanghai 200433, Peoples R China.
We study a Haldane model with nearest neighbor interactions. We find one-dimensional-like collective modes arising due to the interplay of pseudospin and valley degrees of freedom. In the large-band-gap or moderate interaction limit, these excitations are low energy modes lying in the band gap. The dispersion relations are qualitatively different in the trivial insulator phase and Chern insulator phase, thus can be used to identify the topology of the Haldane model with the bulk property. We also discuss how to detect these modes in cold atom systems. An Abelian gauge theory will emerge when a physical current-current interaction is introduced into the Haldane model or the Kane-Mele model.
Physics, Condensed Matter
; TOPOLOGICAL INSULATORS
; FIELD THEORY