Design and Experimental Observation of Valley-Hall Edge States in Diatomic-Graphene-like Elastic Waveguides

Abstract

We report on the design and experimental validation of a two-dimensional phononic elastic waveguide exhibiting topological Valley-Hall edge states. The lattice structure of the waveguide is inspired by the diatomic graphene and it is imprinted in an initially flat plate by means of geometric indentations. The indentations are distributed according to a hexagonal lattice structure which guarantees the existence of Dirac dispersion at the boundary of the Brillouin zone. Starting from this basic material, domain walls capable of supporting edge states can be obtained by contrasting waveguides having broken space inversion symmetry (SIS) achieved by using local resonant elements. Our theoretical study shows that such material maps into the acoustic analog of the quantum valley Hall effect (QVHE) while numerical and experimental results confirm the existence of protected edge states traveling along the walls of topologically distinct domains.

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Cited by in corpus (36)

• Topological Sound
• Tailoring Structure-borne Sound Through Bandgap Engineering in Phononic Crystals and Metamaterials: A Comprehensive Review
• Observation of topologically protected helical edge modes in Kagome elastic plates
• Valley based splitting of topologically protected helical waves in elastic plates
• Theory and Experimental Investigation of the Quantum Valley Hall Effect
• Experimental evidence of robust acoustic valley Hall edge states in a non-resonant topological elastic waveguide
• Self-ordering induces multiple topological transitions for elastic waves in phononic crystals
• Geometrically navigating topological platonic modes around gentle and sharp bends
• Valley-projected edge modes observed in underwater sonic crystals
• Valley-Hall In-Plane Edge States as Building Blocks for Elastodynamic Logic Circuits
• Topological spin-Hall edge states of flexural wave in perforated metamaterial plates
• Valley Anisotropy in Elastic Metamaterials
• Manipulating Topological Valley Modes in Plasmonic Metasurfaces
• Observation of topological gravity-capillary waves in a water wave crystal
• Topological waves guided by a glide-reflection symmetric crystal interface
• Uncovering and experimental realization of multimodal 3D topological metamaterials for low-frequency and multiband elastic wave control
• Synthetic Kramers pair in phononic elastic plates and helical edge states on a dislocation interface
• Observations of symmetry induced topological mode steering in a reconfigurable elastic plate
• Double Dirac Cones and Topologically Non-Trivial Phonons for Continuous, Square Symmetric (C${}_{4v}$ and C${}_{2v}$) Unit Cells
• Broadband Frequency and Spatial On-Demand Tailoring of Topological Wave Propagation Harnessing Piezoelectric Metamaterials
• Tailored Topological Edge Waves via Chiral Hierarchical Metamaterials
• Design of GaAs-based valley phononic crystals with multiple complete phononic bandgaps at ultra-high frequency
• Polarization-dependent and Valley-protected Lamb Waves in Asymmetric Pillared Phononic Crystals
• Non-conventional topological band properties and gapless helical edge states in elastic phononic waveguides with Kekulé distortion
• Tunable three-way valley Hall energy-splitter: venturing beyond graphene-like structures
• Weyl points and topological surface states in a three-dimensional elastic lattice
• Topological transition in spiral elastic valley metamaterials
• Structure-Composition Correspondence in Crystalline Metamaterials for Acoustic Valley-Hall Effect and Unidirectional Sound Guiding
• Granular Graphene: direct observation of zigzag and armchair edge waves
• Tunable bandgaps and symmetry breaking in magneto-mechanical metastructures inspired by multi-layer 2D materials
• Valley-Chern Effect with LC-Resonators: A Modular Platform
• Characterization of elastic topological states using dynamic mode decomposition
• Designing topological acoustic lattices via electroacoustic analogies
• Low-frequency tunable topological interface states in soft phononic crystal cylinders
• Acoustic topological circuitry in square and rectangular phononic crystals
• Topological defect states in elastic phononic plates