• DOI:10.1038/nmat4807
• Corpus ID: 41435454

Valley photonic crystals for control of spin and topology.

@article{Dong2017ValleyPC,
  title={Valley photonic crystals for control of spin and topology.},
  author={Jianwen Dong and Xiaodong Chen and Hanyu Zhu and Yuan Wang and Xiang Zhang},
  journal={Nature materials},
  year={2017},
  volume={16 3},
  pages={
          298-302
        }
}

• Jianwen Dong, Xiaodong Chen, +2 authors Xiang Zhang
• Published 1 March 2017
• Physics
• Nature materials

Photonic crystals offer unprecedented opportunity for light manipulation and applications in optical communication and sensing. 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 and Weyl points. Recently, a new degree of freedom, valley, has been demonstrated in two-dimensional materials. 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.