Energy spectra with respect to μ for the finite chains obtained by numerical diagonalization of the Hamiltonian (1) with parameters: L = 128, θ = 0, t_y/t_x = 0.3, η/t_x = 0.3, and Δ/t_x = 0.1. The numbers of chains are (a) n = 3; (b) n = 4; (c) n = 5; (d) n = 6.