Abstract We show that the photonic crystal (PhC) made of dielectric cuboids with their centers forming a honeycomb lattice is characterized by a ℤ 2 ${\mathbb{ℤ}}_{2}$ topological index when the longer sides of six cuboids point towards the center of hexagonal unit cell. While the C 6v symmetry regarding the center of unit cell is preserved, the C 3 symmetry regarding honeycomb sites is broken, which opens a bandgap in the Dirac dispersion of honeycomb structure and induces a band inversion between p modes and d modes. Rotating cuboids around their individual centers closes the bandgap and reopens a trivial bandgap. We discuss that this feature can be exploited for realizing a reconfigurable topological waveguide.

中文翻译：

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基于电介质长方体蜂窝晶格的可重构拓扑波导

摘要 我们证明了由电介质长方体构成的光子晶体 (PhC) 具有 ℤ 2 ${\mathbb{ℤ}}_{2}$ 拓扑指数，当六个长方体的长边指向朝向六边形晶胞的中心。在保持关于晶胞中心的 C 6v 对称性的同时，关于蜂窝位置的 C 3 对称性被破坏，这在蜂窝结构的狄拉克色散中打开了带隙，并导致 p 模式和 d 模式之间的能带反转。围绕它们各自的中心旋转长方体关闭带隙并重新打开一个微不足道的带隙。我们讨论了可以利用此功能来实现可重构拓扑波导。