Localization of the wave function corresponding to the middle eigenvalue (green plot in Fig. 2). The parameters are chosen as: (a) Δ = 0.2t, η = 0.1, t_A = 0, t_B = 0; (b) Δ = 0.1t, η = 0.2, t_A = 0.1t, t_B = −0.1t; (c) Δ = 0.2t, η = 0.1, t_A = 0.1t, t_B = 0.1t, respectively. The wave functions are concentrated at the edges in the topological region and delocalize over the whole chain in the trivial region (right).