Non-Hermitian topological phases and skin effects in kagome lattices

TL;DR

This paper explores non-Hermitian kagome lattice models exhibiting topological phases and skin effects, revealing complex boundary phenomena and potential realizations in metamaterials.

Contribution

It introduces a class of non-Hermitian kagome models with non-reciprocal hoppings, demonstrating hybrid topological-skin effects and diverse bulk-boundary responses.

Findings

Identification of corner skin modes in different energy regions

Revelation of non-Hermitian skin effects linked to chiral edge states

Potential realization in non-Hermitian metamaterials

Abstract

Non-Hermitian physics has added new ingredients to topological physics, leading to the rising frontier of non-Hermitian topological phases. In this study, we investigate Chern insulator phases emerging from non-Hermitian kagome models with non-reciprocal and pure imaginary next-nearest neighbor hoppings. In the presence or absence of $C_3$ rotation symmetry, hybrid topological-skin effects are explored through the identification of distinct corner skin modes in different energy regions within two band gaps. By employing the dynamical analysis, the underlying physics is revealed from the non-Hermitian skin effects associated with the chiral edge states, leading to diverse non-Hermitian bulk-boundary responses. The simplicity of these kagome models and their rich emergent topological phenomena suggest that they are appealing candidates for studying non-Hermitian topological phases. We further discuss the possible realizations of these models in non-Hermitian metamaterials.