(a) The illustration of the Haldane model on square lattice. Blue and red dots represent A,B sublattices. The blue arrows represent t′ and the dashed blue arrows represent −t′. (b) The particle density distribution around the zero energy vacancy. (c) The energy splitting ΔE between two vacancies as a function of L (the distance of two nearby vacancies). The parameter is t′ = 0.2t. From Ref. [30]. |