Observation of the Layer Hall Effect in Topological Axion Antiferromagnet MnBi2Te4

Prof. SuYang Xu, Department of Chemistry, Harvard University
Zoom Seminar
Guang Bian

While ferromagnets have been known and exploited for millennia, antiferromagnets were only discovered in the 1930s. The elusive nature indicates antiferromagnets’ unique properties: At large scale, due to the absence of global magnetization, antiferromagnets may appear to behave like any non-magnetic material; At the microscopic level, however, the opposite alignment of spins forms a rich internal structure. In topological antiferromagnets, such an internal structure leads to a new possibility, where topology and Berry phase can acquire distinct spatial textures. We study this exciting possibility in an antiferromagnetic Axion insulator, even-layered MnBi2Te4 flakes. We report the observation of a new type of Hall effect, the layer Hall effect, where electrons from the top and bottom layers spontaneously deflect in opposite directions.


A. Gao, et al.  “Layer Hall effect in a 2D topological axion antiferromagnet.” Nature 595, 521 (2021).