Topological Properties of Floquet Winding Bands in a Photonic Lattice

One of the current challenges in creating synthetic materials is engineering those with multiple classes of topological invariants. In our study, we created a synthetic photonic lattice using a two-coupled ring system, which resulted in an anomalous Floquet metal that is gapless in bulk and exhibits two different topological properties. The synthetic lattice has bands with a winding number, which is caused by the breakup of inversion symmetry and results in Bloch sub-oscillations. Additionally, the Floquet nature of the lattice creates well-known anomalous insulating phases with topological edge states. By combining broken inversion symmetry and periodic time modulation, our study suggests the possibility of new phases in lattices subject to Floquet driving.

Reference:  A. F. Adiyatullin, Lavi K. Upreti, et al., Phys. Rev. Lett. 130, 056901 (2023)