Valley and pseudospin-valley topologically protected edge states in symmetric pillared phononic crystals

Abstract

We present a symmetric double-sided pillared phononic crystals (PPnCs) that can emulate both quantum spin Hall effect (QSHE) and quantum valley Hall effect (QVHE) by solely imposing different geometric perturbations. Indeed, the Dirac cones can occur in the low (deep subwavelength) and high frequency regime by judiciously turning the parameters of the attached pillars and even a double Dirac cone can be achieved. We realize the valley-protected, the pseudospin-protected or the pseudospin-valley coupled edge states with the proposed platform. Besides, we show a variety of refraction phenomena (positive, negative and evanescent) of the valley-polarized edge state at the zigzag termination when emulating QVHE. Further, we illustrate the valley-dependent feature of the pseudospin-valley coupled edge state and demonstrate the valley based splitting of the pseudospin-protected edge states in a Y-junction wave guide.

arXiv comment4 figures

References in corpus (17)

• Topological Insulators
• Scheme to Achieve Silicon Topological Photonics
• Colloquium: Topological Band Theory
• Topological Acoustics
• Topologically protected elastic waves in phononic metamaterials
• Topologically-protected refraction of robust kink states in valley photonic crystals
• Visualization of unidirectional optical waveguide using topological photonic crystals made of dielectric material
• Observation of topological valley modes in an elastic hexagonal lattice
• Tunable Acoustic Valley-Hall Edge States in Reconfigurable Phononic Elastic Waveguides
• Topological Phase Transition in Mechanical Honeycomb Lattice
• Pseudospin-valley coupled edge states in a photonic topological insulator
• Observation of topologically protected helical edge modes in Kagome elastic plates
• Subwavelength and directional control of flexural waves in zone-folding induced topological plates
• Scattering-Free Optical Edge States between Heterogeneous Photonic Topological Insulators
• Spiral-based phononic plates: From wave beaming to topological insulators
• Valley based splitting of topologically protected helical waves in elastic plates
• Analysis of the Robustness of Conventional and Topologically Protected Edge States in Phononic Crystal Plates

Cited by in corpus (7)

• Abnormal topological refraction into free medium at sub-wavelength scale in valley phononic crystal plates
• Observations of symmetry induced topological mode steering in a reconfigurable elastic plate
• Broadband Frequency and Spatial On-Demand Tailoring of Topological Wave Propagation Harnessing Piezoelectric Metamaterials
• Subwavelength Su-Schrieffer-Heeger topological modes in acoustic waveguides
• Valley and Valley-like Split-ring Topological Photonic Crystal
• Experimental realization of three-dimensional elastic phononic topological insulator
• Topological defect states in elastic phononic plates