Beyond predicting existence: Unified winding numbers for topological edge states in non-Hermitian quadripartite lattices
Phys. Rev. B 113, 075136 – Published 17 February, 2026
DOI: https://doi.org/10.1103/h5wk-8cdl
Abstract
We present exact analytical solutions for topological edge states, including zero modes and in-gap states, in one-dimensional non-Hermitian quadripartite Su-Schrieffer-Heeger lattices under open boundary conditions. From these solutions, we obtain explicit asymptotic expressions for the edge-state energies and wave functions, and establish rigorous criteria governing their existence and spatial localization. Our results reveal how and under what conditions the non-Hermitian skin effect suppresses or delocalizes edge states through parameter-dependent decay lengths. Furthermore, we introduce for such systems a unified set of topological invariants that not only classify all edge states and restore the bulk-boundary correspondence, but also predict their spatial localization directions. This work thus paves the way for understanding and engineering topological phenomena in a broad class of non-Hermitian multipartite systems, even including those lacking chiral symmetry.