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Prediction and observation of an antiferromagnetic topological insulator

DOI: 10.1038/s41586-019-1840-9 DOI Help

Authors: M. M. Otrokov (Centro de Física de Materiales (CFM-MPC), Centro Mixto CSIC-UPV/EHU; IKERBASQUE, Basque Foundation for Science; Donostia International Physics Center (DIPC); Saint Petersburg State University) , I. I. Klimovskikh (Saint Petersburg State University) , H. Bentmann (Universität Würzburg) , D. Estyunin (Saint Petersburg State University) , A. Zeugner (Technische Universität Dresden) , Z. S. Aliev (Institute of Physics, Azerbaijan National Academy of Sciences) , S. Gaß (Leibniz IFW Dresden) , A. U. B. Wolter (Leibniz IFW Dresden) , A. V. Koroleva (Saint Petersburg State University) , A. M. Shikin (Saint Petersburg State University) , M. Blanco-rey (Donostia International Physics Center (DIPC); Departamento de Física de Materiales UPV/EHU) , M. Hoffmann (Johannes Kepler Universität) , I. P. Rusinov (Saint Petersburg State University; Tomsk State University) , A. Yu. Vyazovskaya (Saint Petersburg State University; Tomsk State University) , S. V. Eremeev (Saint Petersburg State University; Tomsk State University; Institute of Strength Physics and Materials Science, Russian Academy of Sciences) , Yu. M. Koroteev (Tomsk State University; Institute of Strength Physics and Materials Science, Russian Academy of Sciences) , V. M. Kuznetsov (Tomsk State University) , F. Freyse (Elektronenspeicherring BESSY II) , J. Sánchez-barriga (Elektronenspeicherring BESSY II) , I. R. Amiraslanov (Institute of Physics, Azerbaijan National Academy of Sciences) , M. B. Babanly (Institute of Catalysis and Inorganic Chemistry, Azerbaijan National Academy of Science) , N. T. Mamedov (Institute of Physics, Azerbaijan National Academy of Sciences) , N. A. Abdullayev (Institute of Physics, Azerbaijan National Academy of Sciences) , V. N. Zverev (Institute of Solid State Physics, Russian Academy of Sciences) , A. Alfonsov (Leibniz IFW Dresden) , V. Kataev (Leibniz IFW Dresden) , B. Büchner (Leibniz IFW Dresden; Technische Universität Dresden) , E. F. Schwier (Hiroshima Synchrotron Radiation Center, Hiroshima University) , S. Kumar (Hiroshima Synchrotron Radiation Center, Hiroshima University) , A. Kimura (Hiroshima University) , L. Petaccia (Elettra Sincrotrone Trieste) , G. Di Santo (Elettra Sincrotrone Trieste) , R. C. Vidal (Universität Würzburg) , S. Schatz (Universität Würzburg) , K. Kißner (Universität Würzburg) , M. Unzelmann (Universität Würzburg) , C. H. Min (Universität Würzburg) , Simon Moser (Advanced Light Source) , T. R. F. Peixoto (Universität Würzburg) , F. Reinert (Universität Würzburg) , A. Ernst (Johannes Kepler Universität; Max-Planck-Institut für Mikrostrukturphysik) , P. M. Echenique (Centro de Física de Materiales (CFM-MPC), Centro Mixto CSIC-UPV/EHU; Donostia International Physics Center (DIPC); Departamento de Física de Materiales UPV/EHU) , A. Isaeva (Leibniz IFW Dresden; Technische Universität Dresden) , E. V. Chulkov (Centro de Física de Materiales (CFM-MPC), Centro Mixto CSIC-UPV/EHU; Donostia International Physics Center (DIPC); Saint Petersburg State University; Departamento de Física de Materiales UPV/EHU)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Nature , VOL 576 , PAGES 416 - 422

State: Published (Approved)
Published: December 2019

Abstract: Magnetic topological insulators are narrow-gap semiconductor materials that combine non-trivial band topology and magnetic order. Unlike their nonmagnetic counterparts, magnetic topological insulators may have some of the surfaces gapped, which enables a number of exotic phenomena that have potential applications in spintronics, such as the quantum anomalous Hall effect and chiral Majorana fermions. So far, magnetic topological insulators have only been created by means of doping nonmagnetic topological insulators with 3d transition-metal elements; however, such an approach leads to strongly inhomogeneous magnetic and electronic properties of these materials, restricting the observation of important effects to very low temperatures. An intrinsic magnetic topological insulator—a stoichiometric well ordered magnetic compound—could be an ideal solution to these problems, but no such material has been observed so far. Here we predict by ab initio calculations and further confirm using various experimental techniques the realization of an antiferromagnetic topological insulator in the layered van der Waals compound MnBi2Te4. The antiferromagnetic ordering that MnBi2Te4 shows makes it invariant with respect to the combination of the time-reversal and primitive-lattice translation symmetries, giving rise to a ℤ2 topological classification; ℤ2 = 1 for MnBi2Te4, confirming its topologically nontrivial nature. Our experiments indicate that the symmetry-breaking (0001) surface of MnBi2Te4 exhibits a large bandgap in the topological surface state. We expect this property to eventually enable the observation of a number of fundamental phenomena, among them quantized magnetoelectric coupling and axion electrodynamics. Other exotic phenomena could become accessible at much higher temperatures than those reached so far, such as the quantum anomalous Hall effect and chiral Majorana fermions.

Journal Keywords: Electronic devices; Electronic properties and materials; Magnetic properties and materials; Spintronics; Topological insulators

Subject Areas: Materials, Physics


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