Edge states and corner modes in second-order topological phononic crystal plates

Abstract

We realize an elastic second-order topological insulator hosting both one-dimensional gapped edge states and zero-dimensional in-gap corner modes in the double-sided pillared phononic crystal plates with square lattice. Changing the width of two neighbor pillars breaks the inversion symmetry and induces the band inversion to emulate the quantum spin Hall effect where the gapless edge states are obtained. Further breaking the space-symmetry at interface, the gapless edge states are gapped and inducing the edge topological transitions and then giving rise to the zero-dimensional in-gap corner modes. Our work offers a novel way for elastic wave trapping and robustly guiding.

References in corpus (19)

• Quantum Spin Hall Effect and Topological Phase Transition in HgTe Quantum Wells
• Quantized Electric Multipole Insulators
• Higher-Order Topological Insulators
• Topological Acoustics
• $(d-2)$-dimensional edge states of rotation symmetry protected topological states
• Observation of a phononic quadrupole topological insulator
• Observation of topological valley transport of sound in sonic crystals
• Acoustic higher-order topological insulator on a Kagome lattice
• Demonstration of a quantized microwave quadrupole insulator with topologically protected corner states
• Topologically protected elastic waves in phononic metamaterials
• Floquet Topological Insulators for Sound
• Topologically-protected refraction of robust kink states in valley photonic crystals
• Observation of second-order topological insulators in sonic crystals
• Topologically protected acoustic helical edge states and interface states in strongly coupled metamaterial ring lattices
• Experimental Realization of Acoustic Chern Insulator
• Electronically Programmable Photonic Molecule
• Experimental realization of on-chip topological nanoelectromechanical metamaterials
• Higher-order topological insulators protected by inversion and rotoinversion symmetries
• Observation of topologically protected helical edge modes in Kagome elastic plates

Cited by in corpus (4)

• Double Dirac Cones and Topologically Non-Trivial Phonons for Continuous, Square Symmetric (C${}_{4v}$ and C${}_{2v}$) Unit Cells
• Multidimensional sound propagation in 3D high-order topological sonic insulator
• Observation of emergent Dirac physics at the surfaces of acoustic higher-order topological insulators
• Polarization-independent second-order photonic topological corner states