Layer Hall effect in a 2D topological axion antiferromagnet

Gao A, Liu YF, Hu C, Qiu JX, Tzschaschel C, Ghosh B, Ho SC, Berube D, Chen R, Sun H, Zhang Z, Zhang XY, Wang YX, Wang N, Huang Z, Felser C, Agarwal A, Ding T, Tien HJ, Akey A, Gardener J, Singh B, Watanabe K, Taniguchi T, Burch KS, Bell DC, Zhou BB, Gao W, Lu HZ, Bansil A, Lin H, Chang TR, Fu L, Ma Q, Ni N, Xu SY (2021)

Publication Type: Journal article

Publication year: 2021

Journal

Nature Nature Research

Book Volume: 595

Pages Range: 521-525

Journal Issue: 7868

DOI: 10.1038/s41586-021-03679-w

Abstract

Whereas ferromagnets have been known and used for millennia, antiferromagnets were only discovered in the 1930s1. At large scale, because of the absence of global magnetization, antiferromagnets may seem to behave like any non-magnetic material. At the microscopic level, however, the opposite alignment of spins forms a rich internal structure. In topological antiferromagnets, this internal structure leads to the possibility that the property known as the Berry phase can acquire distinct spatial textures2,3. Here we study this possibility in an antiferromagnetic axion insulator—even-layered, two-dimensional MnBi2Te4—in which spatial degrees of freedom correspond to different layers. We observe a type of Hall effect—the layer Hall effect—in which electrons from the top and bottom layers spontaneously deflect in opposite directions. Specifically, under zero electric field, even-layered MnBi2Te4 shows no anomalous Hall effect. However, applying an electric field leads to the emergence of a large, layer-polarized anomalous Hall effect of about 0.5e2/h (where e is the electron charge and h is Planck’s constant). This layer Hall effect uncovers an unusual layer-locked Berry curvature, which serves to characterize the axion insulator state. Moreover, we find that the layer-locked Berry curvature can be manipulated by the axion field formed from the dot product of the electric and magnetic field vectors. Our results offer new pathways to detect and manipulate the internal spatial structure of fully compensated topological antiferromagnets4–9. The layer-locked Berry curvature represents a first step towards spatial engineering of the Berry phase through effects such as layer-specific moiré potential.

Involved external institutions

Indian Institute of Technology Bombay IN India (IN) Harvard University US United States (USA) (US) University of California Los Angeles (UCLA) US United States (USA) (US) Boston College US United States (USA) (US) Tata Institute of Fundamental Research (TIFR) IN India (IN) National Institute of Materials Science (NIMS) JP Japan (JP) Nanyang Technological University (NTU) SG Singapore (SG) Southern University of Science and Technology CN China (CN) Northeastern University US United States (USA) (US) Academia Sinica / 中央研究院 TW Taiwan (TW) National Cheng Kung University TW Taiwan (TW) Massachusetts Institute of Technology (MIT) US United States (USA) (US) Max-Planck-Institut für Chemische Physik fester Stoffe (MPI CPfS) / Max Planck Institute for Chemical Physics of Solids DE Germany (DE)

How to cite

APA:

Gao, A., Liu, Y.-F., Hu, C., Qiu, J.-X., Tzschaschel, C., Ghosh, B.,... Xu, S.-Y. (2021). Layer Hall effect in a 2D topological axion antiferromagnet. Nature, 595(7868), 521-525. https://dx.doi.org/10.1038/s41586-021-03679-w

MLA:

Gao, Anyuan, et al. "Layer Hall effect in a 2D topological axion antiferromagnet." Nature 595.7868 (2021): 521-525.

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