Fig. 4: Topological quasi 0D bound states.
From: Emerging topological bound states in Haldane model zigzag nanoribbons
Results from numerical diagonalization in topologically non-trivial regions for different widths: (a, e, i) Ny = 4; (b, f, j) Ny = 6; (c, g, k) Ny = 8; (d, h, l) Ny = 10. For different values of m for each of the widths considered (respectively 0, 0.5, 0.8, 0.92), the top row reports the bands of the strips with PBC along x (a1) and the mid row reports the low energy spectra of the corresponding OBC counterparts, obtained for strips of length 20a (e), 40a (f), 80a (g), 160a (h). The values of m chosen for each strip belong to the regions marked with a star in Fig. 3. A doublet of degenerate modes (marked in blue and orange) is visible inside each gap of the OBC spectra: these correspond to bound states localized at the ends of the strips. The 1D probability density profiles of the states associated to the eigenvalue n∘10 (marked in orange) of each of the spectra (e–h) are reported in the bottom row (i–l) as a function of the position for the left half of the various strips (x < 0). For each of these plots, the insets show the unprojected probability densities. The model parameters are set to t1 = 1, t2 = 0.3 and ϕ = π/2.
