Realization of an intrinsic ferromagnetic topological state in MnBi₈Te₁₃

Journal Article · Wed Jul 22 00:00:00 EDT 2020 · Science Advances

DOI:https://doi.org/10.1126/sciadv.aba4275· OSTI ID:1641878

Hu, Chaowei ^[1]; Ding, Lei ^[2]; Gordon, Kyle N. ^[3]; Ghosh, Barun ^[4]; Tien, Hung-Ju ^[5]; Li, Haoxiang ^[3]; Linn, A. Garrison ^[3]; Lien, Shang-Wei ^[5]; Huang, Cheng-Yi ^[6]; Mackey, Scott ^[1]; Liu, Jinyu ^[1]; Reddy, P. V. Sreenivasa ^[5]; Singh, Bahadur ^[7]; Agarwal, Amit ^[4]; Bansil, Arun ^[7]; Song, Miao ^[8]; Li, Dongsheng ^[8]; Xu, Su-Yang ^[9]; Lin, Hsin ^[6]; Cao, Huibo ^[2] ; Chang, Tay-Rong ^[10]; Dessau, Dan ^[11]; Ni, Ni ^[1]

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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. Department of Physics, National Cheng Kung University, Tainan 701, Taiwan., Center for Quantum Frontiers of Research & Technology (QFort), Tainan 701, Taiwan., Physics Division, National Center for Theoretical Sciences, Hsinchu, Taiwan.
11. Department of Physics, University of Colorado, Boulder, CO 80309, USA., Center for Experiments on Quantum Materials, University of Colorado, Boulder, CO 80309, USA.

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.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). High Flux Isotope Reactor (HFIR); SLAC National Accelerator Laboratory, Menlo Park, CA (United States). Stanford Synchrotron Radiation Lightsource (SSRL)
• Sponsoring Organization: Council of Scientific & Industrial Research (CSIR); National Science Foundation (NSF); Taiwan Ministry of Science and Technology (MOST); USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division
• Grant/Contract Number: AC02-05CH11231; AC02-76SF00515; AC05-00OR22725; SC0011978; SC0019275
• OSTI ID: 1641878
• Alternate ID(s): OSTI ID: 1649161
• Journal Information: Science Advances, Journal Name: Science Advances Journal Issue: 30 Vol. 6; ISSN 2375-2548
• Publisher: AAAS
• Country of Publication: United States
• Language: English

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36 MATERIALS SCIENCE