Topological Anderson Insulator in Disordered Photonic Crystals
Gui-Geng Liu, Yihao Yang, Xin Ren, Haoran Xue, Xiao Lin, Yuan-Hang Hu, Hong-xiang Sun, Bo Peng, Peiheng Zhou, Y. D. Chong, Baile Zhang
Abstract
Recent studies have revealed the counterintuitive possibility that increasing disorder can turn a topologically trivial insulator into a nontrivial insulator, called a topological Anderson insulator (TAI). Here, we propose and experimentally demonstrate a photonic TAI in a two-dimensional disordered gyromagnetic photonic crystal in the microwave regime. We directly observe the disorder-induced topological phase transition from a trivial insulator to a TAI with robust chiral edge states. We also demonstrate topological heterostructures that host edge states at interfaces between domains with different disorder parameters.