Observation of topological valley modes in an elastic hexagonal lattice

Vila, Javier; Pal, Raj Kumar; Ruzzene, Massimo

doi:10.1103/physrevb.96.134307

Cited by 252 publications

(195 citation statements)

References 40 publications

(50 reference statements)

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“…However, due to the large separation in k-space of the two valleys, valley-dependent topological invariants can be defined and used to classify the topological states of the different lattices. This approach, usually referred to as quantum valley Hall effect (QVHE), was recently investigated for application to fluidic acoustic waveguides 9,12 , as well as elastic plates with local resonators 28,29 .…”

Section: Introductionmentioning

confidence: 99%

“…1(a)). Compared to the previous studies 28, 29 , we take a fully continuum modeling approach which provides a general methodology of analysis and allows mapping the topological behavior all the way back to the massless (or massive when SIS is broken) Dirac equation. Also, an in-depth study of the occurrence of edge states, either at domain walls or at the lattice boundaries, is presented.…”

Section: Introductionmentioning

confidence: 99%

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Tunable Acoustic Valley–Hall Edge States in Reconfigurable Phononic Elastic Waveguides

2018

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This study investigates the occurrence of acoustic topological edge states in a 2D phononic elastic waveguide due to a phenomenon that is the acoustic analogue of the quantum valley Hall effect. We show that a topological transition takes place between two lattices having broken space inversion symmetry due to the application of a tunable strain field. This condition leads to the formation of gapless edge states at the domain walls, as further illustrated by the analysis of the bulk-edge correspondence and of the associated topological invariants. Although time reversal symmetry is still intact in these systems, the edge states are topologically protected when inter-valley mixing is either weak or negligible. Interestingly, topological edge states can also be triggered at the boundary of a single domain if boundary conditions are properly selected. We also show that the static modulation of the strain field allows tuning the response of the material between the different supported edge states.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Tunable Acoustic Valley–Hall Edge States in Reconfigurable Phononic Elastic Waveguides

2018

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“…Over the past few years, “valleytronics” has emerged as an area where valley, a binary degree of freedom, has a potential to be an excellent candidate of information carrier. The concept of valley has also been introduced into different kinds of physical systems, such as photonics, acoustics, and elastics . In the photonic community, researchers have found that domain walls between two types of inversion‐breaking photonic crystals, that is, valley‐Hall photonic topological insulators (PTIs), could support topologically nontrivial valley‐polarized kink states.…”

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confidence: 99%

Valley‐Hall Photonic Topological Insulators with Dual‐Band Kink States

Chen

Zhang

et al. 2019

Advanced Optical Materials

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Extensive researches have revealed that valley, a binary degree of freedom (DOF), can be an excellent candidate of information carrier. Recently, valley DOF is introduced into photonic systems, and several valley‐Hall photonic topological insulators (PTIs) are experimentally demonstrated. However, in the previous valley‐Hall PTIs, topological kink states only work at a single frequency band, which limits potential applications in multiband waveguides, filters, communications, and so on. To overcome this challenge, here a valley‐Hall PTI, where the topological kink states exist at two separated frequency bands, is experimentally demonstrated in a microwave substrate‐integrated circuitry. Both the simulated and experimental results demonstrate the dual‐band valley‐Hall topological kink states are robust against the sharp bends of the internal domain wall with negligible intervalley scattering. This work may pave the way for multichannel substrate‐integrated photonic devices with high efficiency and high capacity for information communications and processing.

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“…The edge states can also be selectively excited according to the angular selection rule. Experimental observation of valley-chiral edge states in an elastic hexagonal lattice has also been reported recently [101].…”

Section: Reviewmentioning

confidence: 95%

Breaking the barriers: advances in acoustic functional materials

Yang

et al. 2017

National Science Review

181

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Acoustics is a classical field of study that has witnessed tremendous developments over the past 25 years. Driven by the novel acoustic effects underpinned by phononic crystals with periodic modulation of elastic building blocks in wavelength scale and acoustic metamaterials with localized resonant units in subwavelength scale, researchers in diverse disciplines of physics, mathematics, and engineering have pushed the boundary of possibilities beyond those long held as unbreakable limits. More recently, structure designs guided by the physics of graphene and topological electronic states of matter have further broadened the whole field of acoustic metamaterials by phenomena that reproduce the quantum effects classically. Use of active energy-gain components, directed by the parity-time reversal symmetry principle, has led to some previously unexpected wave characteristics. It is the intention of this review to trace historically these exciting developments, substantiated by brief accounts of the salient milestones. The latter can include, but are not limited to, zero/negative refraction, subwavelength imaging, sound cloaking, total sound absorption, metasurface and phase engineering, Dirac physics and topology-inspired acoustic engineering, non-Hermitian parity-time synthetic active metamaterials, and one-way propagation of sound waves. These developments may underpin the next generation of acoustic materials and devices, and offer new methods for sound manipulation, leading to exciting applications in noise reduction, imaging, sensing and navigation, as well as communications.

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Observation of topological valley modes in an elastic hexagonal lattice

Cited by 252 publications

References 40 publications

Tunable Acoustic Valley–Hall Edge States in Reconfigurable Phononic Elastic Waveguides

Tunable Acoustic Valley–Hall Edge States in Reconfigurable Phononic Elastic Waveguides

Valley‐Hall Photonic Topological Insulators with Dual‐Band Kink States

Breaking the barriers: advances in acoustic functional materials

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