Multiple topological phase transitions in a gyromagnetic photonic crystal

Abstract
We present the design of a tunable two-dimensional photonic crystal that exhibits multiple topological phases, including a conventional insulator phase, a quantum spin Hall phase, and a quantum anomalous Hall phase under different combinations of geometric parameters and external magnetic fields. Our photonic crystal enables a platform to study the topology evolution attributed to the interplay between crystalline symmetry and time-reversal symmetry. A four-band tight-binding model unambiguously reveals that the topological property is associated with the pseudospin orientations and that it is characterized by the spin Chern number. The emerging quantum anomalous Hall phase features a single helical edge state that is locked by a specific pseudospin. Simulation results demonstrate that the propagation of such a single helical edge state is robust against magnetic impurities. Potential applications, such as spin splitters, are described.

Citation
Chen Z-G, Mei J, Sun X-C, Zhang X, Zhao J, et al. (2017) Multiple topological phase transitions in a gyromagnetic photonic crystal. Physical Review A 95. Available: http://dx.doi.org/10.1103/PhysRevA.95.043827.

Acknowledgements
The work described here was supported by King Abdullah University of Science and Technology and the National Natural Science Foundation of China (Grants No. 11274120 and No. 11574087).

Publisher
American Physical Society (APS)

Journal
Physical Review A

DOI
10.1103/PhysRevA.95.043827

Additional Links
https://journals.aps.org/pra/abstract/10.1103/PhysRevA.95.043827

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