Realization of an intrinsic ferromagnetic topological state in MnBi8Te13

Chaowei Hu; Lei Ding; Kyle N Gordon; Barun Ghosh; Hung-Ju Tien; Haoxiang Li; A Garrison Linn; Shang-Wei Lien; Cheng-Yi Huang; Scott Mackey; Jinyu Liu; P V Sreenivasa Reddy; Bahadur Singh; Amit Agarwal; Arun Bansil; Miao Song; Dongsheng Li; Su-Yang Xu; Hsin Lin; Huibo Cao; Tay-Rong Chang; Dan Dessau; Ni Ni

doi:10.1126/sciadv.aba4275

Realization of an intrinsic ferromagnetic topological state in MnBi₈Te₁₃

Sci Adv. 2020 Jul 22;6(30):eaba4275. doi: 10.1126/sciadv.aba4275. eCollection 2020 Jul.

Authors

Chaowei Hu¹, Lei Ding², Kyle N Gordon³, Barun Ghosh⁴, Hung-Ju Tien⁵, Haoxiang Li³, A Garrison Linn³, Shang-Wei Lien⁵, Cheng-Yi Huang⁶, Scott Mackey¹, Jinyu Liu¹, P V Sreenivasa Reddy⁵, Bahadur Singh⁷, Amit Agarwal⁴, Arun Bansil⁷, Miao Song⁸, Dongsheng Li⁸, Su-Yang Xu⁹, Hsin Lin⁶, Huibo Cao², Tay-Rong Chang^{5

10

11}, Dan Dessau^{3

12}, Ni Ni¹

Affiliations

¹ Department of Physics and Astronomy and California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA.
² Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
³ Department of Physics, University of Colorado, Boulder, CO 80309, USA.
⁴ Department of Physics, Indian Institute of Technology-Kanpur, Kanpur 208016, India.
⁵ Department of Physics, National Cheng Kung University, Tainan 701, Taiwan.
⁶ Institute of Physics, Academia Sinica, Taipei 11529, Taiwan.
⁷ Department of Physics, Northeastern University, Boston, MA 02115, USA.
⁸ Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA 99352, USA.
⁹ Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA.
¹⁰ Center for Quantum Frontiers of Research & Technology (QFort), Tainan 701, Taiwan.
¹¹ Physics Division, National Center for Theoretical Sciences, Hsinchu, Taiwan.
¹² Center for Experiments on Quantum Materials, University of Colorado, Boulder, CO 80309, USA.

Abstract

Novel magnetic topological materials pave the way for studying the interplay between band topology and magnetism. However, an intrinsically ferromagnetic topological material with only topological bands at the charge neutrality energy has so far remained elusive. Using rational design, we synthesized MnBi8Te13, a natural heterostructure with [MnBi₂Te₄] and [Bi₂Te₃] layers. Thermodynamic, transport, and neutron diffraction measurements show that despite the adjacent [MnBi₂Te₄] being 44.1 Å apart, MnBi₈Te₁₃ manifests long-range ferromagnetism below 10.5 K with strong coupling between magnetism and charge carriers. First-principles calculations and angle-resolved photoemission spectroscopy measurements reveal it is an axion insulator with sizable surface hybridization gaps. Our calculations further demonstrate the hybridization gap persists in the two-dimensional limit with a nontrivial Chern number. Therefore, as an intrinsic ferromagnetic axion insulator with clean low-energy band structures, MnBi₈Te₁₃ serves as an ideal system to investigate rich emergent phenomena, including the quantized anomalous Hall effect and quantized magnetoelectric effect.

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