Valley-dependent corner states in honeycomb photonic crystals without inversion symmetry
Valley-dependent corner states in honeycomb photonic crystals without inversion symmetry
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DOI：
10.1364/oe.427222
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发表时间：
2021-06-07
期刊：
影响因子：
3.8
通讯作者：
Wakabayashi, Katsunori
中科院分区：
文献类型：
--
作者：
Huyen Thanh Phan;Liu, Feng;Wakabayashi, Katsunori
利用平面波展开和有限元方法研究了无反演对称性的蜂窝状光子晶体的拓扑态。在蜂窝格点中反演对称性的破缺导致了相反的拓扑谷指数，即，动量空间中谷依赖的陈数我们发现在60度角上出现拓扑角态，而在其他角上没有，这可以理解为谷陈数在角上的符号翻转。我们的研究结果提供了一个实验上可行的平台，探索谷依赖的高阶拓扑结构的光子系统。(C)根据OSA开放获取出版协议的条款，2021年美国光学学会
We study topological states of honeycomb photonic crystals in the absence of inversion symmetry using plane wave expansion and finite element methods. The breaking of inversion symmetry in honeycomb lattice leads to contrasting topological valley indices, i.e., the valley-dependent Chern numbers in momentum space. We find that the topological corner states appear for 60 degrees degree corners, but absent for other corners, which can be understood as the sign flip of valley Chern number at the corner. Our results provide an experimentally feasible platform for exploring valley-dependent higher-order topology in photonic systems. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement