Topological corner states and bound states in the continuum in layer-stacked heterostructures
Phys. Rev. Applied 25, 054059 – Published 21 May, 2026
DOI: https://doi.org/10.1103/vnrf-d29t
Abstract
In recent years, multilayer structures that tune topological phases through the regulation of the layer degree of freedom have attracted significant attention. Compared with monolayer systems, multilayer systems with interlayer coupling can host a richer variety of topological phases, among which those with heterogeneous layers remain insufficiently explored. In this paper, based on the two-dimensional Su-Schrieffer-Heeger model, we investigate bilayer and trilayer heterostructures composed of vertically stacked layers with different topological properties. We find that variations in the interlayer coupling strength can induce topological phase transitions in the system, significantly altering the number of corner states in these topological structures. The evolution of the number of corner states is further directly demonstrated by calculating the multipole chiral numbers. We performed acoustic simulations to verify the variation in the number of corner states in bilayer and trilayer heterostructures, and further proposed a new scheme for constructing topological bound states in the continuum. Our work experimentally demonstrates the effectiveness of this phenomenon in acoustic systems and offers a practical route to realize reconfigurable acoustic devices for wave-energy confinement, topological filtering, and sensing, leveraging controllable layer coupling in compact architectures.
