Topological phase transitions and Weyl semimetal phases in chiral photonic metamaterials

Han, Ning; Liu, Jianlong; Gao, Yang; Zhou, Keya; Liu, Shutian

doi:10.1088/1367-2630/ac6f78

Cited by 8 publications

(3 citation statements)

References 65 publications

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“…As a result, it is acceptable to disregard the dispersion mode of the permeability tensor elements. Notably, in a reasonable range, the thickness and the layered materials of the ferrite-metal superlattice can be adjustable [30,[33][34][35]. It provides us with the flexibility to obtain the needed equivalent parameters of the gyromagnetic medium in figure 1.…”

Section: Ideal Weyl Points and Berry Fluxes Of The Gmsmentioning

confidence: 99%

“…In the GMs, the nontrivial topological feature of the equal frequency surfaces (Weyl points) can be identified by the Chern numbers (C). Mathematically, the Chern numbers (C) of the equifrequency surfaces and Weyl points are depicted as the surface integral of the Berry curvature [Ω(k)] in the momentum space [34]:…”

Section: Ideal Weyl Points and Berry Fluxes Of The Gmsmentioning

confidence: 99%

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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: Ideal Weyl Points and Berry Fluxes Of The Gmsmentioning

confidence: 99%

Section: Ideal Weyl Points and Berry Fluxes Of The Gmsmentioning

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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“…In recent years, the studied three-dimensional Weyl semimetals have attracted lots of attention in physics and material communities. It has triggered many striking phenomena, such as negative magnetoresistance effects, pseudo-gauged fields, and the curious Hall and quantum-Hall effects of light [17][18][19][20].…”

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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Tunable topological interface states via a parametric system in composite lattices with/without symmetric elements

Cui,

Yang,

Han

et al. 2024

Appl. Math. Mech.-Engl. Ed.

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Topological phase transitions and Weyl semimetal phases in chiral photonic metamaterials

Cited by 8 publications

References 65 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

Tunable topological interface states via a parametric system in composite lattices with/without symmetric elements

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