Ms. Huyen Thanh Phan has published her work on the topological corner states in honeycomb photonic crystals without inversion symmetry in Optics Express.

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^° 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.

Paper information

Title: Valley-dependent corner states in honeycomb photonic crystals without inversion symmetry

Authors: Huyen Thanh Phan(Kwansei Gakuin University), Feng Liu(Ningbo University), and Katsunori Wakabayashi(Kwansei Gakuin University)

Optics Express, vol. 29, 18277 (2021). doi: https://doi.org/10.1364/OE.427222