The entanglement spectrum. Panels (a) and (b) are non-interacting cases for U = 0 while panels (c) and (d) are U = 0.25 and U = −0.25. Other parameters are chosen as: (a) Δ = 0.2t, η = 0.1, t_A = 0.1t, t_B = 0.1t; (b), (c), and (d) Δ = 0.1t, η = 0.2, t_A = 0.1t, t_B =−0.1t, respectively.