Topological Pseudospin Hall Effect and Multi-frequency Corner Modes in Kagome-based Lattices

TL;DR

This paper explores novel topological phenomena in extended kagome lattices, including multiple corner states and tunable pseudospin Hall effects, broadening the control of wave propagation in classical systems.

Contribution

It introduces two new kagome-derived lattice designs supporting diverse topological edge and corner modes with lower symmetry and greater tunability than previous models.

Findings

Multiple groups of corner states identified.

Parametric tunability of pseudospin Hall effect demonstrated.

Type-II corner states achieved without long-range interactions.

Abstract

Topological phases and modes, including pseudospin-Hall-selective edge transport and corner states, provide robust control of wave propagation and modal confinement in classical wave platforms. Under a tight-binding framework, we theoretically investigate two lattice designs derived from the kagome lattice. These extended kagome lattices support a series of localized modes, including pseudospin-Hall-like topological edge states and corner modes in different bandgaps and frequencies, which were not only achieved under lower lattice symmetries than Wu-Hu lattices, but also enable more degrees of freedom in topological and localized modes. By introducing two types of extended kagome lattices with different topological properties, multiple interesting phenomena, including newly emerged multiple groups of corner states, parametric tunable pseudospin Hall effect, and type-II corner states without long-range interactions, are found in theoretical models, which are possible and viable to achieve in artificial classical systems such as photonic, acoustic, or electrical circuits.