Observation of the axion quasiparticle in 2D MnBi2Te4 - Jian-Xiang Qiu; Barun Ghosh; Jan Schütte-Engel; Tiema Qian; Michael Smith; Yueh-Ting Yao; Junyeong Ahn; Yu-Fei Liu; Anyuan Gao; Christian Tzschaschel; Houchen Li; Ioannis Petrides; et al. (Nature, 2025)