SSH Chain — Topological Band Structure

Su-Schrieffer-Heeger model: 1D topological insulator with protected edge states
H(k) = (t + t'cos k)σ_x + t'sin k · σ_y  ·  W = ∮ dk ∂_k φ(k) / 2π ∈ {0,1}

Hopping Parameters

t = 1.00
t' = 0.40
N = 14

Topology

Winding number W—
Gap size |E_gap|—
Edge states—
Phase—
Bulk-boundary correspondenceW edge modes

The SSH model is the simplest 1D topological insulator. When t' > t (intercell stronger), the winding number W = 1 and the chain is topologically non-trivial — two exponentially localized zero-energy edge states appear, protected by chiral symmetry. When t > t' (intracell stronger), W = 0 and the chain is topologically trivial — no edge states. This is the bulk-boundary correspondence. The phase transition at t = t' closes the gap.