Topological insulator of ultra cold atoms in bichromatic optical lattices
We investigate the effect of a strong bichromatic deformation to the $\mathbbZ_2$ topological insulator in ultracold atomic system proposed by B. Béri and N. R. Cooper, Phys.Rev.Lett. 107, 145301 (2011). Large insulating gap of this system allows for examination of strong perturbations. We conclude that the $\mathbbZ_2$ topological character of the system is robust against a large global perturbation which breaks the inversion symmetry but preserves the time-reversal symmetry.