Magneto-electric response and Quantum Anomalous Hall Effect in Topological Antiferromagnets

ORAL

Abstract

I will discuss the magneto-electric and transport properties of thin films formed from bulk normal and antiferromagnetic topological insulators. In the thick film limit, both systems have the quantized magneto-electric response properties (QTME) that are characteristic of topological insulators. In non-magnetic case, thin films with surface magnetism exhibit a quantized anomalous Hall effect when the magnetizations on the top and bottom surfaces are parallel, and a QTME response when the magnetizations have opposite orientations and the films are sufficiently thick. I will present a unified picture [1] of both effects that associates finite thickness corrections to the QTME with non-locality in the side-wall current response function, emphasizing that the side-wall response is non-zero only near the surface. In the magnetic case, the anomalous Hall effect vanishes when the product of time-reversal and inversion is a good quantum number [2,3], and the magneto-electric response then has both surface and bulk contributions that are quantized only when summed [4]. Quantum anomalous Hall effects occur in many configurations of magnetic topological insulator thin films [5], including in some collinear configurations in which the total spin magnetization vanishes [6].

*C.L. and A.H.M. were sponsored by the Army Research Office under Grant Number W911NF-16-1-0472. R.J.M. and O.H. were supported by the Center for Advancement of Topological Semimetals, an Energy Frontier Research Center funded by the U.S. Department of Energy Office of Science, Office of Basic Energy Sciences, through the Ames Laboratory under Contract No. DEAC02-07CH11358. N. P., A. P. and C. M. C. were supported by the Faculty of Technology at Linnaeus University and by the Swedish Research Council under Grant Number: 621-2014-4785.

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Publication: [1] Pournaghavi N, Pertsova A, MacDonald AH, Canali C. Non-local sidewall response and finite thickness corrections to the topological magnetoelectric effect in thin films. arXiv:2107.02410. (2021).
[2] C. Lei, S. Chen, and A. H. MacDonald, "Magnetized topological insulator multilayers" Proc. Natl. Acad. Sci. U.S.A. 117, 27224 (2020).
[3] C. Lei, and A. H. MacDonald. "Gate-tunable quantum anomalous Hall effects in MnBi2Te4 thin films." Phys. Rev. Mater. 5, L051201 (2021).
[4] C. Lei and A. H. MacDonald. "Surface-Bulk Partition of the Topological Magnetoelectric Effect". To be prepared.
[5] C. Lei, O. Heinonen, A. H. MacDonald, and R. J. McQueeney. "Metamagnetism of few-layer topological antiferromagnets." Phys. Rev. Mater. 5, 064201 (2021).
[6] C. Lei, O. Heinonen, R. J. McQueeney, and A. H. MacDonald. "Quantum Anomalous Hall Effect in Perfectly Compensated Collinear Antiferromagnetic Thin Films." arXiv:2110.00890 (2021).

Presenters

  • Chao Lei

    • University of Texas at Austin

Authors

  • Chao Lei

    • University of Texas at Austin

  • Nezhat Pournaghavi

    • Linnaeus Univ

  • Anna Pertsova

    • NORDITA

  • Carlo M Canali

    • Linnaeus Univ

  • Olle Heinonen

    • Argonne National Laboratory
    • Materials Science Division, Argonne National Laboratory, Lemont, IL 60439, USA

  • Robert J McQueeney

    • Ames Laboratory and Iowa State University
    • Iowa State University
    • Ames Laboratory

  • Allan H MacDonald

    • University of Texas at Austin