Non-Hermitian chiral skin effect of topological edge states
Phys. Rev. B 114, 055102 – Published 6 July, 2026
DOI: https://doi.org/10.1103/gdcf-ty8d
Abstract
This work systematically investigates the non-Hermitian chiral skin effect (NCSE) for topological edge states in a square-lattice Haldane model with staggered potential. We clarify two physically distinct mechanisms underlying NCSE: (i) boundary on-site gain/loss that introduces a complex momentum, and (ii) boundary nonreciprocal hopping that endows edge states with a complex Fermi velocity, a new mechanism unexplored in previous work. We show that the complex-Fermi-velocity mechanism yields three unique features absent in the gain/loss NCSE: a linear complex energy spectrum, particle-hole symmetry, and energy-dependent spatial separation of edge modes. We further provide a unified comparative framework for both mechanisms and propose a feasible LC circuit scheme to experimentally realize the NCSE via nonreciprocal hopping. Our results establish that the NCSE is a family of effects arising from distinct non-Hermitian perturbations, greatly extending the understanding and controllability of chiral skin phenomena in open topological systems.
