The recent realizations of topological valley phase in photonic crystal, an analog of gapped valleytronic materials in electronic system, are limited to the valley Chern number of one. In this letter, we present a new type of valley phase that can have large valley Chern number of two or three. The valley phase transitions between the different valley Chern numbers (from one to three) are realized by changing the configuration of the unit cell. We demonstrate that these new topological phases can guide the wave propagation robustly along the domain wall of sharp bent. Our results are promising for the exploration of new topological phenomena in photonic systems.

中文翻译：

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大谷陈数的拓扑光子晶体

光子晶体中拓扑谷相的最新实现是电子系统中带隙谷电子材料的一种模拟，仅限于陈数的谷。在这封信中，我们提出了一种新型的谷相，它可以有两个或三个大的谷陈数。不同谷陈数（从一到三）之间的谷相变是通过改变晶胞的配置来实现的。我们证明了这些新的拓扑相可以沿着急剧弯曲的畴壁稳健地引导波传播。我们的结果有望用于探索光子系统中的新拓扑现象。