Revealing the hidden Dirac gap in a topological antiferromagnet using Floquet-Bloch manipulation

ORAL

Abstract

Manipulating solids using the time-periodic drive of a laser pulse is a promising route to generate new phases of matter. Whether such `Floquet-Bloch' manipulation can be achieved in topological magnetic systems with disorder has so far been unclear. In this work, we realize Floquet-Bloch manipulation of the Dirac surface-state mass of the topological antiferromagnet (AFM) MnBi2Te4. Using time- and angle-resolved photoemission spectroscopy (tr-ARPES), we show that opposite helicities of mid-infrared circularly polarized light result in substantially different Dirac mass gaps in the AFM phase, despite the equilibrium Dirac cone being massless. We explain our findings in terms of a Dirac fermion with a random mass. Our results underscore Floquet-Bloch manipulation as a powerful tool for controlling topology even in the presence of disorder, and for uncovering properties of materials that may elude conventional probes.

**This work was supported by the Quantum Sensing and Quantum Materials, an Energy Frontier Research Center funded by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences (BES), under Award No.DE-SC0021238, from the EPiQS program of the Gordon and Betty Moore Foundation, Grant GBMF11069, and from the Illinois Materials Research Science and Engineering Center, supported by the National Science Foundation MRSEC program under NSF Award No. DMR-1720633.

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Presenters

  • Nina Bielinski

    • University of Illinois at Urbana-Champaign

Authors

  • Nina Bielinski

    • University of Illinois at Urbana-Champaign

  • Rajas Chari

    • University of Illinois at Urbana-Champaign

  • Julian May-Mann

    • University of Illinois at Urbana-Champai
    • Stanford

  • Soyeun Kim

    • Stanford University

  • Jack Zwettler

    • University of Illinois at Urbana-Champaign

  • Yujun Deng

    • Stanford Univeristy

  • Anuva Aishwarya

    • University of Illinois at Urbana Champaign
    • Harvard University

  • Subhajit Roychowdhury

    • Max Planck Institute for Chemical Physic

  • Chandra Shekhar

    • Max Planck Institute for Chemical Physics of Solids

  • Makoto Hashimoto

    • SLAC - Natl Accelerator Lab

  • Donghui Lu

    • SLAC - Natl Accelerator Lab

  • Jiaqiang Yan

    • Oak Ridge National Laboratory

  • Claudia Felser

    • Max Planck Institute for Chemical Physic
    • Max Planck Institute for Chemical Physics of Solids

  • Vidya Madhavan

    • University of Illinois at Urbana-Champaign
    • University of Illinois Urbana-Champaign

  • Zhi-Xun Shen

    • Stanford University
    • stanford university

  • Taylor Hughes

    • University of Illinois at Urbana-Champaign

  • Fahad Mahmood

    • University of Illinois Urbana-Champaign