Exact analytical edge states in the extended Su-Schrieffer-Heeger model
The authors derived exact analytical expressions for zero-energy edge states of a semi-infinite extended Su-Schrieffer-Heeger (eSSH) model, which includes hopping beyond nearest neighbors. They established a bulk-boundary correspondence using the winding number of the bulk Hamiltonian, showing that topological phase transitions are linked to changes in this invariant.