Type-II Dirac points and topological Fermi arcs in nonlocal metamaterials

Li, Mingzhu; Han, Ning; Peng, Liang; Zhang, Shuang

doi:10.1103/physrevb.106.235303

Cited by 6 publications

(2 citation statements)

References 55 publications

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“…Objects with identical topological invariants are considered topologically equivalent. The concepts and foundational principles of photonic topological materials are historically rooted in research on the topological phase of condensed matter systems [4][5][6][7]. Recently, topological photonics has emerged as a promising platform for exploring topological phenomena, due to its diversity and ease of manipulation.…”

Section: Introductionmentioning

confidence: 99%

Cladding-free Fermi arc surface states and topological directional couplers in ideal photonic Weyl metamaterials

Li,

Han,

Wang

et al. 2024

Phys. Scr.

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Photons can freely propagate in the vacuum state, so the vacuum is not a trivial insulator, but a conductor for photons. Because of this reason, in topological photonics, the domain wall structures with opposite effective mass terms as a cladding to confine electromagnetic waves have to be adopted to demonstrate the topological edge/surface waves and Fermi arc surface states. In this work, based on the ideal Weyl gyromagnetic metamaterials (GMs), we demonstrate that can be realized the cladding-free Fermi arc surface states with high field localization on the boundary. In the GMs, the ideal Weyl semimetal phase exists due to the dispersionless longitudinal modes. The claddingfree Fermi arc surface states connect the projections of the Weyl points with opposite chirality at the boundary owing to the bulk-edge correspondence of the vacuum-GMs system. Full-wave simulations further demonstrate that that chiral surface waves can seamlessly propagate forward around various types of defects without experiencing scattering or backward reflection. Remarkably, different types of topological directional couplers are achieved by utilizing the cladding-free Fermi arc surface states in the ideal GMs. We theoretically demonstrate that the physical mechanism of realizing the topological directional couplers is caused by the single coupling channel between the cladding-free Fermi arc surface states and scatterers of the vacuum-GMs system. Moreover, the controllable propagation and topological directional coupling of the cladding-free Fermi arc surface states can be realized by changing the gyromagnetic parameters and boundary configurations in the topological directional couplers. Our work could provide more flexibility for the cladding-free and directional coupling topological devices.

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Section: Introductionmentioning

confidence: 99%

Cladding-free Fermi arc surface states and topological directional couplers in ideal photonic Weyl metamaterials

Li,

Han,

Wang

et al. 2024

Phys. Scr.

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“…The Fermi arc surface states are topologically protected, and their lengths can be used to measure the topological strength of the system [26,27]. The Fermi arc surface states can bring new capabilities to manipulate wave propagation in classical systems, including electromagnetic, acoustic, and elastic waves [28][29][30][31][32].…”

Section: Introductionmentioning

confidence: 99%

Fermi arc surface state and topological switch in the gyromagnetic metamaterials

Li¹,

Han

et al. 2023

New J. Phys.

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A landmark feature of the Weyl system is that it possesses the Fermi arc surface states. In this work, we demonstrate that the Fermi arc surface states connect the vacuum state and the Weyl points of gyromagnetic metamaterials (GMs). The nonzero Chern numbers and Berry phases show the nontrivial topological property of the GMs in momentum space. Full-wave simulations demonstrate that the chiral surface waves on the boundary between the GMs and vacuum state can achieve robustness against sharp corners of step-type configurations. Remarkably, the topological switch can be realized by adopting the Fermi arc surface states between two different GMs. We theoretically prove that the physical mechanism of realizing topological switch is caused by different gap Chern numbers of the material system. Moreover, the direction of the topological switch can be operated by manipulating the gyromagnetic parameters of the GMs in the “button” region. Our work may provide more flexibility for the flexible and robust topological devices.

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Topological photonics in three and higher dimensions

Han,

Xi,

Meng

et al. 2024

APL Photonics

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Topological photonics is a rapidly developing field that leverages geometric and topological concepts to engineer and control the characteristics of light. Currently, the research on topological photonics has expanded from traditional one-dimensional (1D) and two-dimensional (2D) to three-dimensional (3D) and higher-dimensional spaces. However, most reviews on topological photonics focus on 1D and 2D systems, and a review that provides a detailed classification and introduction of 3D and higher-dimensional systems is still missing. Here, we review the photonic topological states in 3D and higher-dimensional systems on different platforms. Moreover, we discuss internal connections between different photonic topological phases and look forward to the future development direction and potential applications of 3D and higher-dimensional systems.

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Type-II Dirac points and topological Fermi arcs in nonlocal metamaterials

Cited by 6 publications

References 55 publications

Cladding-free Fermi arc surface states and topological directional couplers in ideal photonic Weyl metamaterials

Cladding-free Fermi arc surface states and topological directional couplers in ideal photonic Weyl metamaterials

Fermi arc surface state and topological switch in the gyromagnetic metamaterials

Topological photonics in three and higher dimensions

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