Total reflection and large Goos-Hänchen shift in a semi-Dirac system

Xiang, Hongxiang; Zhai, Feng

doi:10.1103/physrevb.109.035432

Cited by 3 publications

(1 citation statement)

References 68 publications

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“…Unlike the usual isotropic model in the well-celebrated graphene [22] and other metamaterials [23], the anisotropic model has a modified nearest neighbor (NN) hopping term and is a tunable parameter [24,25]. This tunability merges two Dirac cones in the band structure and results in the topological phase transition (see figure 1(b)) from band-inversion, semi-Dirac, and insulating phase characterized by different transport signatures [26][27][28][29] and of potential in designing valleytronics device [30][31][32]. Apart from photonic [33], polariton materials [34] and α-dice lattice [35][36][37], the anisotropic honeycomb lattices are also expected in anisotropic graphene [38] and phosphorene [19,39], monolayer arsenene [40] and silicene oxide [41].…”

Section: Introductionmentioning

confidence: 99%

Designing edge states from fractional polarization insulators

Chan,

Fu,

Ang

et al. 2024

J. Phys.: Condens. Matter

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We theoretically investigated disconnected dispersive edge states in an anisotropic honeycomb lattice without chiral symmetry. When both mirror and chiral symmetries are present, this system is defined by a topological quantity known as fractional polarization (FP) term and exhibits a bulk band gap, classifying it as an FP insulator. While the FP insulator accommodates robust, flat topological edge states (TES), it also offers the potential to engineer these edge states by deliberately disrupting a critical symmetry that safeguards the underlying topology. These symmetry-breaking terms allow the edge states to become dispersive and generate differing configurations along the open boundaries. Furthermore, disconnected helical-like and chiral-like edge states analogous to TES seen in quantum spin and anomalous hall effect are achieved by the finite size effect, not possible from the symmetry-breaking terms alone. The demonstration of manipulating these edge states from a FP insulator can open up new avenues in constructing devices that utilize topological domain walls.

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Section: Introductionmentioning

confidence: 99%

Designing edge states from fractional polarization insulators

Chan,

Fu,

Ang

et al. 2024

J. Phys.: Condens. Matter

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Goos-Hänchen shift for relativistic particles based on Dirac's equation

Zhou,

Zhang,

Fan

et al. 2024

Phys. Rev. A

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Dual-band semi-Dirac cones in two-dimensional photonic crystal and zero-index material

Ji,

Zhang,

2024

Acta Phys. Sin.

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Semi-Dirac cones, a type of unique dispersion relation, always exhibit a series of interesting transport properties, such as electromagnetic topological transitions and anisotropic electromagnetic transmission. Recently, dual-band semi-Dirac cones have been found in three-dimensional photonic crystals, presenting great potential in electromagnetic wave regulation. However, to the best of our knowledge, there has been no report on dual-band semi-Dirac cones and their applications in two-dimensional photonic crystals, most two-dimensional systems have only realized semi-Dirac cones at a single frequency. Therefore, we aim to achieve dual-band semi-Dirac cones in two-dimensional photonic crystals. In this work, a type of two-dimensional photonic crystal that comprises a square lattice of elliptical cylinders embedded in air is proposed. By rotating the elliptical cylinders and adjusting their sizes appropriately, accidental degeneracies at two different frequencies are achieved simultaneously in the center of the Brillouin zone. Using k · p perturbation theory, the dispersion relations near the two degenerate points are proved to be nonlinear in one direction, and linear in other directions, as shown in Figures (c) and (d). These results indicate that the double accidental degenerate points are two semi-Dirac points with different frequencies, and two different semi-Dirac cones, i.e., dual-band semi-Dirac cones, are realized simultaneously in the photonic crystal designed by us. More interestingly, the dual-band semi-Dirac cones exhibit opposite linear and nonlinear dispersion relations along the major axis and minor axis of the ellipse. And our photonic crystal can be equivalent to an impedance-matched double-zero index material in the direction of linear dispersion and a single-zero index material in the direction of nonlinear dispersion, which is demonstrated by the perfect transmission in the straight waveguide and wavefront shaping capabilities of electromagnetic waves. Based on the different properties of the equivalent zero-refractive-indices near two semi-Dirac points frequencies, a designed Y-type waveguide can be used to realize frequency separation by directing plane waves of different frequencies out along different ports, just as shown in Figures (e) and (f). We believe that our work is meaningful in broadening the exploration of the band structures of two-dimensional photonic crystals and providing greater convenience for the regulation of electromagnetic waves.

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Total reflection and large Goos-Hänchen shift in a semi-Dirac system

Cited by 3 publications

References 68 publications

Designing edge states from fractional polarization insulators

Designing edge states from fractional polarization insulators

Goos-Hänchen shift for relativistic particles based on Dirac's equation

Dual-band semi-Dirac cones in two-dimensional photonic crystal and zero-index material

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