Topologically nontrivial magnetism in Cr<sub>2</sub>Te<sub>3</sub> ultrathin films

ORAL

Abstract

Transition metal chalcogenides are versatile for realizing topological phenomena. Quasi 2D Cr2Te3 MBE films enable control over charge/spin degrees of freedom, leveraged by strain tunability at the substrate/film interface. Cr2Te3 films display perpendicular magnetic anisotropy with a Curie temperature of ~ 160 K for thickness of 20 unit cells, whose structure and magnetic properties are examined by transmission electron microscopy, polarized neutron reflectometry and scanning tunneling microscopy. This is accompanied by rich magnetotransport properties: apart from the ordinary Hall effect with linear field dependence, the anomalous Hall effect manifests a unique temperature-dependent sign reversal. Novel topological Hall effect (THE) appears, related to the emergence of magnetic skyrmions, nanometer-sized quasiparticles with topological spin textures. The magnitude of the THE is tunable via interface strain that can be varied by film thickness and choice of substrate (Al2O3 and SrTiO3). The effective interface-driven tunability of non-coplanar spin textures in Cr2Te3 ultrathin films offers new opportunities for spintronics.

*Supported by ARO W911NF-19-2-0015, W911NF-19-2-0041 and W911NF-20-2-0061, NSF DMR 1700137, ONR N00014-16-1-2657 and N00014-20-1-2306 and CIQM NSF 1231319.

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Presenters

  • Hang Chi

    • Massachusetts Institute of Technology
    • Francis Bitter Magnet Laboratory, Plasma Science and Fusion Center, Massachusetts Institute of Technology

Authors

  • Hang Chi

    • Massachusetts Institute of Technology
    • Francis Bitter Magnet Laboratory, Plasma Science and Fusion Center, Massachusetts Institute of Technology

  • Yunbo Ou

    • Massachusetts Institute of Technology
    • Francis Bitter Magnet Laboratory, Plasma Science and Fusion Center, Massachusetts Institute of Technology

  • Tim B. Eldred

    • North Carolina State University

  • Wenpei Gao

    • University of California, Irvine
    • North Carolina State University

  • Valeria Lauter

    • Oak Ridge National Lab
    • Oak Ridge National Laboratory

  • Michael Dreyer

    • University of Maryland, College Park
    • University of Maryland
    • Physics, University of Maryland
    • Department of Physics, University of Maryland

  • Robert E Butera

    • Laboratory for Physical Sciences

  • George J. de Coster

    • U.S. Army CCDC Army Research Laboratory
    • Sensors & Electron Devices Directorate, U.S. Army Research Laboratory

  • Charles Rong

    • U.S. Army CCDC Army Research Laboratory

  • Donald E Heiman

    • Northeastern University

  • Jagadeesh S Moodera

    • Massachusetts Institute of Technology
    • Plasma Science and Fusion Center, and Francis Bitter Magnet Laboratory, and Department of Physics,, Massachusetts Institute of Technology
    • Physics, Massachusetts Institute of Technology
    • Department of Physics, Massachusetts Institute of Technology