Dominik Kriegner
The anomalous Hall effect, commonly observed in metallic magnets, has been established to originate from the time-reversal symmetry breaking by an internal macroscopic magnetization in ferromagnets or by a noncollinear magnetic order. Here we observe a spontaneous anomalous Hall signal in the absence of an external magnetic field in MnTe, which is a semiconductor with a collinear antiparallel magnetic ordering of Mn moments, and altermagnetic symmetry due to the non-magnetic Te atoms.