An antiferromagnetic topological insulator

The discovery of a variety of different topological materials has been driven by theoretical predictions followed up by experimental realizations. However, the prediction of magnetic and strongly correlated topological phases is more challenging, and experimentally their study has been largely limited to the study of magnetically doped topological insulators. Mikhail Otrokov and coworkers predict and observe an intrinsic antiferromagnetic topological insulator in the van der Waals material MnBi₂Te₄. The bandgap in the topological surface state that is due to the presence of magnetic order is evidenced by ab initio calculations and photoemission spectroscopy. This material discovery opens up the exploration of magnetic topological phases and effects, such as axion states or the quantized magnetoelectric effect.