Quantum anomalous Hall effect in intrinsic magnetic topological insulator MnBi2Te4

By Yujun Deng, Y. Yu, M. Shi, Zhongxun Guo, Zihan Xu, Jing Wang, Xian Hui Chen, Yuanbo Zhang. Science, 2019

1,325 citations recorded by the source corpus.

Quantum anomalous Hall goes intrinsic Quantum anomalous Hall effect—the appearance of quantized Hall conductance at zero magnetic field—has been observed in thin films of the topological insulator Bi2Se3 doped with magnetic atoms. The doping, however, introduces inhomogeneity, reducing the temperature at which the effect occurs. Two groups have now observed quantum anomalous Hall effect in intrinsically magnetic materials (see the Perspective by Wakefield and Checkelsky). Serlin et al. did so in twisted bilayer graphene aligned to hexagonal boron nitride, where the effect enabled the switching of magnetization with tiny currents. In a complementary work, Deng et al. observed quantum anomalous Hall effect in the antiferromagnetic layered topological insulator MnBi2Te4. Science, this issue p. 900, p. 895; see also p. 848 Transport measurements indicate quantized Hall conductance without a magnetic field. In a magnetic topological insulator, nontrivial band topology combines with magnetic order to produce exotic states of matter, such as quantum anomalous Hall (QAH) insulators and axion insulators. In this work, we probe quantum transport in MnBi2Te4 thin flakes—a topological insulator with intrinsic magnetic order. In this layered van der Waals crystal, the ferromagnetic layers couple antiparallel to each other; atomically thin MnBi2Te4, however, becomes ferromagnetic when the sample has an odd number of septuple layers. We observe a zero-field QAH effect in a five–septuple-layer specimen at 1.4 kelvin, and an external magnetic field further raises the quantization temperature to 6.5 kelvin by aligning all layers ferromagnetically. The results establish MnBi2Te4 as an ideal arena for further exploring various topological phenomena with a spontaneously broken time-reversal symmetry.

Subfields: Atomic and Molecular Physics, and Optics, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/3c534a0cbee825e761e0949c6070ee838f5813bb

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Citations in the corpus

Colloquium : Quantum anomalous Hall effect (2022, background): “The QAH effects in magnetically doped TIs (Chang et al., 2013a, 2015b; Mogi et al., 2015), in the intrinsic magnetic TI MnBi2Te4 (Deng et al., 2020), and in moiré materials (Li et al., 2021e; Serlin et al., 2020) have comparable and low onset temperatures.”
Angle-resolved photoemission studies of quantum materials (2020, neutral): “A recent development which promises to shed light on this issue was the prediction of MnBi2Te4 as an antiferromagnetic TI (Li et al., 2019b; Otrokov et al., 2019; Zhang et al., 2019a), with the first published ARPES results reporting a gap of ∼ 100 meV (Lee et al., 2019; Vidal et al., 2019; Zeugner ”