A Universal Mirror-stacking Approach for Constructing Topological Bound States in the Continuum

Abstract

Bound states in the continuum (BICs) are counter-intuitive localized states with eigenvalues embedded in the continuum of extended states. Recently, nontrivial band topology is exploited to enrich the BIC physics, resulted in topological BICs (TBICs) with extraordinary robustness against perturbations or disorders. Here, we propose a simple but universal mirror-stacking approach to turn nontrivial bound states of any topological monolayer model into TBICs. Physically, the mirror-stacked bilayer Hamiltonian can be decoupled into two independent subspaces of opposite mirror parities, each of which directly inherits the energy spectrum information and band topology of the original monolayer. By tuning the interlayer couplings, the topological bound state of one subspace can move into and out of the continuum of the other subspace continuously without hybridization. As representative examples, we construct one-dimensional first-order and two-dimensional higher-order TBICs, and demonstrate them unambiguously by acoustic experiments. Our findings will expand the research implications of both topological materials and BICs.

5 figures,accepted by Phys.Rev.Lett

References in corpus (9)

• Topological Photonics
• Electric Multipole Moments, Topological Multipole Moment Pumping, and Chiral Hinge States in Crystalline Insulators
• Topological nature of bound states in the radiation continuum
• Observation of a localized flat-band state in a photonic Lieb lattice
• Observation of bound states in Lieb photonic lattices
• Acoustic realization of quadrupole topological insulators
• Moire quasi-bound states in the continuum
• Observation of degenerate zero-energy topological states at disclinations in an acoustic lattice
• Bound states in the continuum through environmental design

Cited by in corpus (10)

• Applications of Bound States in the Continuum in Photonics
• Higher-Order Topological In-Bulk Corner State in Pure Diffusion Systems
• Observation of Topological Corner State Arrays in Photonic Quasicrystals
• Topological metals constructed by sliding quantum wire arrays
• Deployable Nanoelectromechanical Bound States in the Continuum Enabled by GHz Lamb Wave Phononic Crystals on LiNbO3 Thin Films
• Dimensional hierarchy of topological bound states in the continuum
• Topology reconstruction for asymmetric systems by isomorphic mapping or perturbation approximation
• Fragile dislocation modes in obstructed atomic topological phases
• Uncovering Bound States in the Continuum in InSb nanowire networks
• Layer-number parity induced topological phase transition