Topological Anderson insulator in disordered photonic crystals

• Main Authors: Liu, Gui-Geng, Yang, Yihao, Ren, Xin, Xue, Haoran, Lin, Xiao, Hu, Yuan-Hang, Sun, Hong-xiang, Peng, Bo, Zhou, Peiheng, Chong, Yidong, Zhang, Baile
• Other Authors: School of Physical and Mathematical Sciences
• Format: Article
• Language: English
• Published: 2020
• Subjects: Science::Physics; Anderson Insulator; Photonic Crystals
• Online Access: https://hdl.handle.net/10356/145168
• Institution: Nanyang Technological University

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.