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

## Abstract

The quantum anomalous Hall effect1,2 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 electronics5,6. Here, we report a Berry-curvature-driven4,7 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 gap8,9,10, 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.

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## Data availability

Source data are available for this paper. All other data that support the plots within this paper and other findings of this study are available from the corresponding author upon reasonable request.

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## Acknowledgements

We wish to acknowledge A. Millis for helpful insights and J. Hone for critical reading of the manuscript. This work was supported by the US National Science Foundation grants DMR-1420634 (Columbia-CCNY MRSEC) and HRD-1547830, and by the Polish National Science Center grant 2016/21/B/ST3/02565. Irradiations on SIRIUS platform were supported by EMIR&A under project 18-9136. Computational support was provided by Virginia Tech Advanced Research for Computing and the San Diego Supercomputer Center under DMR-060009N.

## Author information

Authors

### Contributions

Experiments were designed by L.K.-E. and H.D. Device fabrication and the transport and magnetic measurements were performed by H.D. Structural and elemental characterization of the crystals grown by I.V.F. was done by K.S. and J.B. A.W. and J.S. characterized samples by ferromagnetic resonance. Electron irradiations were conducted by M.K. with the assistance of Z.C. and H.D. ARPES studies were performed by T.H. and L.P. K.P. calculated the DFT band structure. A.B.G. and J.C. calculated AHE conductance from the Berry curvature. Data analysis was done by H.D. and L.K.-E. L.K.-E. wrote the manuscript with the input from H.D.

### Corresponding author

Correspondence to Lia Krusin-Elbaum.

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### Competing interests

The authors declare no competing interests.

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## Supplementary information

### Supplementary Information

Supplementary Discussion and Supplementary Figures 1–14

## Source data

### Source Data Fig. 1

Source data for Figure 1.

### Source Data Fig. 2

Source data for Figure 2.

### Source Data Fig. 3

Source data for Figure 3.

### Source Data Fig. 4

Source data for Figure 4.

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Deng, H., Chen, Z., Wołoś, A. et al. High-temperature quantum anomalous Hall regime in a MnBi2Te4/Bi2Te3 superlattice. Nat. Phys. (2020). https://doi.org/10.1038/s41567-020-0998-2