Non-Hermitian topological phases and skin effects in kagome lattices

Non-Hermitian physics has added ingredients to topological physics, leading to the rising frontier of non-Hermitian topological phases. In this paper, we investigate Chern insulator phases emerging from non-Hermitian kagome models with nonreciprocal 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.