Valley photonic crystals for control of spin and topology
Valley photonic crystals for control of spin and topology
复制标题
用于控制自旋和拓扑的谷光子晶体
DOI：
10.1038/nmat4807
复制
发表时间：
2017-03-01
期刊：
影响因子：
41.2
通讯作者：
Zhang, Xiang
中科院分区：
文献类型：
--
作者：
Dong, Jian-Wen;Chen, Xiao-Dong;Zhang, Xiang
光子晶体为光操纵和光通信和传感应用提供了前所未有的机会（1-4）。对具有非零规范场的光子晶体和超材料中拓扑结构的探索激发了许多有趣的光学现象，如单向输运和Weyl点（5-10）。最近，一个新的自由度，谷，已被证明在二维材料（11-15）。在这里，我们提出了具有电磁对偶对称性但反转对称性破缺的谷型光子晶体的概念。我们观察到光子谷霍尔效应起源于谷相关的自旋分裂体带，即使在拓扑平凡的光子晶体。谷自旋锁定行为导致在块状谷光子晶体内的选择性净自旋流。我们还显示了独立控制的山谷和拓扑结构，在一个单一的系统，一直追求在电子系统中，导致拓扑保护的平边状态。Valley光子晶体不仅提供了一条观测非平凡态的途径，而且还为利用自旋相关输运的集成光子学和信息处理中的器件应用开辟了道路。
Photonic crystals offer unprecedented opportunity for light manipulation and applications in optical communication and sensing(1-4). Exploration of topology in photonic crystals and metamaterials with non-zero gauge field has inspired a number of intriguing optical phenomena such as one-way transport andWeyl points(5-10). Recently, a new degree of freedom, valley, has been demonstrated in two-dimensional materials(11-15). Here, we propose a concept of valley photonic crystals with electromagnetic duality symmetry but broken inversion symmetry. We observe photonic valley Hall effect originating from valley-dependent spin-split bulk bands, even in topologically trivial photonic crystals. Valley-spin locking behaviour results in selective net spin flow inside bulk valley photonic crystals. We also show the independent control of valley and topology in a single system that has been long pursued in electronic systems, resulting in topologically-protected flat edge states. Valley photonic crystals not only offer a route towards the observation of non-trivial states, but also open the way for device applications in integrated photonics and information processing using spin-dependent transportation.