High-temperature quantum anomalous Hall regime in a MnBi₂Te₄/Bi₂Te₃ superlattice

The quantum anomalous Hall effect^1,2 is a fundamental transport response of a topological insulator in zero magnetic field. Its physical origin is a result of an intrinsically inverted electronic band structure and ferromagnetism³, and its most important manifestation is the dissipationless flow of chiral charge currents at the edges of the system⁴, a property that has the potential to transform future quantum electronics^5,6. Here, we report a Berry-curvature-driven^4,7 anomalous Hall regime at temperatures of several Kelvin in the magnetic topological bulk crystals in which Mn ions self-organize into a period-ordered MnBi₂Te₄/Bi₂Te₃ superlattice. Robust ferromagnetism of the MnBi₂Te₄ monolayers opens a surface gap^8–10, and when the Fermi level is tuned to be within this gap, the anomalous Hall conductance reaches an e²/h quantization plateau, which is a clear indication of chiral transport through the edge states. The quantization in this regime is not obstructed by the bulk conduction channels and therefore should be present in a broad family of topological magnets.