Fig. 1: Design of a 3D magnetic Weyl photonic crystal.
From: Topological antichiral surface states in a magnetic Weyl photonic crystal
a Conceptual illustration of antichiral surface states (red and blue arrows) that propagate in the same direction on opposite surfaces of a 3D gyromagnetic Weyl photonic crystal. b The unit cell of 3D gyromagnetic photonic crystal consisting of two sandwiched gyromagnetic rods (red and blue fan-shaped rods) sitting on the perforated metallic plate. The gyromagnetic rods at different sublattice sites of the honeycomb lattice are oppositely magnetized by pairs of permanent magnets (silver fan-shaped rods) with reversed biasing direction. The red (blue) arrows indicate the biased magnetic fluxes along +z (−z) directions. The lattice constants in the xy-plane and z-direction are a = 7.5 mm and h = 6.5 mm, and the other geometrical parameters are r1 = 1.3 mm, h1 = 2.5 mm, h2 = 2 mm and h3 = 1 mm, respectively. c Top view of a unit cell of perforated metallic plates with geometrical parameters r2 = 2.9 mm, d = 1.5 mm, l1 = 0.4 mm, l2 = 0.25 mm. d Calculated bulk band structure of the magnetic Weyl photonic crystals along high-symmetry lines. Orange and purple spheres represent two pairs of frequency-shifted WPs carrying opposite topological charges of +1 and −1. e 3D bulk Brillouin zone with ideal type-II WPs. f Simulated 2D surface dispersions of A-type (blue curved sheet) and B-type (red curved sheet) surfaces. g–i Simulated surface dispersions for fixed values of g kz = 0π/h, h kz = 0.38π/h and i kz = 1π/h, respectively. The blue (red) lines indicate the A-type (B-type) surface state dispersion, respectively, and cyan regions represent the projected bulk states.
