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Interplay of Magnetism and Phonons in Ultrafast Dynamics of Magnetic Topological Insulator MnBi<sub>2</sub>Te<sub>4</sub>

ORAL

Abstract

We investigate the ultrafast dynamics of the antiferromagnetic topological insulator MnBi2Te4 using a combination of high-sensitivity transient reflectivity and time-resolved magneto-optical measurements. MnBi2Te4 has recently generated substantial interest as a stoichiometric topological insulator with intrinsic magnetism, hosting novel symmetry-protected states that are topologically nontrivial. Furthermore, theory predicts that the magnetic ground state lies in proximity to several competing orders due to frustration from large next-nearest neighbor AFM exchange along with strong coupling between electronic, magnetic, and lattice degrees of freedom. This opens the door for the optical control and engineering of nonequilibrium states of matter. Here, we report clear signatures of spin-phonon coupling in the ultrafast magnetization dynamics. We provide a detailed account of these dynamic features as a function of magnetic field applied along various crystalline axes, temperature, and pump conditions.

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Presenters

  • Peter Kim

    University of California, San Diego, UC San Diego

Authors

  • Peter Kim

    University of California, San Diego, UC San Diego

  • Maxwell Poore

    University of California, San Diego, UC San Diego

  • Hari Padmanabhan

    Pennsylvania State University, Department of Material Science and Engineering, Penn State University

  • Vladimir A Stoica

    Pennsylvania State University, Argonne National Laboratory, Department of Physics, University of Michigan

  • Seng Huat Lee

    Pennsylvania State University, Department of Physics, Pennsylvania State University, Physics, The Pennsylvania State University, 2D Crystal Consortium, Materials Research Institute, Penn State University, Materials Research Institute, Pennsylvania State University

  • Zhiqiang Mao

    Pennsylvania State University, Department of Physics, Penn State University, The Pennsylvania State University, Penn State University, Physics, Penn State University, Department of Physics, Pennsylvania State University, Department of Physics, The Pennsylvania State University, Physics, The Pennsylvania State University, Physics, Pennsylvania State University, Department of Materials Science and Engineering, Pennsylvania State University

  • Venkatraman Gopalan

    Pennsylvania State University, Material Science and Engineering, Pennsylvania State University, Department of Material Science and Engineering, Penn State University, Department of Materials Science and Engineering, Pennsylvania State University, Materials Science and Engineering, Pennsylvania State University

  • Richard Averitt

    University of California, San Diego, University of California San Diego, UC San Diego, Physics, University of California San Diego, Department of Physics, University of California, San Diego, University of California