Photonic axion insulator

• 成果类型: Article
• 署名作者: Liu, Gui-Geng; Mandal, Subhaskar; Xi, Xiang; Wang, Qiang; Devescovi, Chiara; Morales-Perez, Antonio; Wang, Ziyao; Yang, Linyun; Banerjee, Rimi; Long, Yang; Meng, Yan; Zhou, Peiheng; Gao, Zhen; Chong, Yidong; Garcia-Etxarri, Aitzol; Vergniory, Maia G.; Zhang, Baile
• 署名单位: Nanyang Technological University; Westlake University; Dongguan University of Technology; Nanjing University; Swiss Federal Institutes of Technology Domain; ETH Zurich; University of Basque Country; Southern University of Science & Technology; University of Electronic Science & Technology of China; Southern University of Science & Technology; Nanyang Technological University; Basque Foundation for Science; Max Planck Society; University of Sherbrooke; University of Sherbrooke
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-11583
• DOI: 10.1126/science.adr5234
• 发表日期: 2025-01-10
• 页码: 162-166
• 关键词: fractional chern insulators; quantum hall state; realization

摘要

Axions, hypothetical elementary particles that remain undetectable in nature, can arise as quasiparticles in three-dimensional crystals known as axion insulators. Previous implementations of axion insulators have largely been limited to two-dimensional systems, leaving their topological properties in three dimensions unexplored in experiment. Here, we realize an axion insulator in a three-dimensional photonic crystal and probe its topological properties. Demonstrated features include half-quantized Chern numbers on each surface that resembles a fractional Chern insulator, unidirectional chiral hinge states forming topological transport in three dimensions, and arithmetic operations between fractional and integer Chern numbers. Our work experimentally establishes the axion insulator as a three-dimensional topological phase of matter and enables chiral states to form complex, unidirectional three-dimensional networks through braiding.