SSH Model — Topological Edge States
Su-Schrieffer-Heeger Chain · Winding Number · Bulk-Boundary Correspondence
Parameters
Intracell hopping v
0.3
Intercell hopping w
1.0
On-site potential Δ
0.0
Chain length N
20
Disorder strength δ
0.0
New disorder
TOPOLOGICAL (ν=1)
H(k) = (v+w cos k)σx + w sin k·σy
winding ν = ½∮ dk ∂ₖφ(k)
ν=1 if w>v → edge states at E=0
SSH model (1979): 1D chain with alternating hoppings. Topological phase (w>v): winding number ν=1 → zero-energy edge states protected by chiral symmetry. Bulk-boundary correspondence: ν bulk invariant = # edge modes. Paradigm of topological insulators.