Zhao-Xian Chen, An Chen, Yu-Gui Peng, Zheng-Wei Li, Bin Liang*, 

Jing Yang*, Xue-Feng Zhu*, Yan-Qing Lu, and Jian-Chun Cheng*

Observation of acoustic Floquet π modes in a time-varying lattice

Phys. Rev. B 109, L020302

DOI: https://doi.org/10.1103/PhysRevB.109.L020302