Mapping out transient topological states in graphene by dichroic time-resolved photoemission

ORAL

Abstract

We study the build-up of the Floquet-Chern insulator state in graphene and its implications in time- and angle-resolved photoemission (ARPES). In particular, we show that the circular dichroism in the angular distribution is directly related to the induced pseudospin texture and thus the Berry curvature of the Floquet band structure. Our conclusions are corroborated by realistic time-dependent simulation under experimentally relevant conditions. Including electron-electron and electron-phonon scattering, we reveal the crucial role of scattering mechanisms for the effective thermalization of the Floquet band structure. These calculations are combined with accurate onestep calculations, yielding an excellent description of the circular dichroism in ARPES (CD-ARPES). Albeit the system is highly excited, we show that CD-ARPES provides the unique possibility of discerning light-engineered topological properties of the effective band structure and the Floquet side bands.

*We acknowledge financial support from the Swiss National Science Foundation via NCCR MARVEL and the European Research Council via ERC-2015-AdG-694097 and ERC Consolidator Grant No. 724103, and the Alexander von Humboldt Foundation for its support with a Lynen scholarship.

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Presenters

  • Michael Schueler

    • Stanford Univ

Authors

  • Michael Schueler

    • Stanford Univ

  • Umberto De Giovannini

    • Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany
    • Max Planck Institute for the Structure and Dynamics of Matter
    • Max Planck Inst Structure & Dynamics of Matter

  • Hannes Huebener

    • Max Planck Institute for the Structure and Dynamics of Matter
    • Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany

  • Angel Rubio

    • Theory Department, Max Planck Institute for the Structure and Dynamics of Matter
    • Center for Computational Quantum Physics (CCQ), The Flatiron Institute
    • Max Planck Institute for Structure and Dynamics of Matter
    • Department of Physics, Columbia University, New York, New York 10027, USA
    • Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany
    • Max Planck Institute for the Structure and Dynamics of Matter
    • Structure and Dynamics of Matter, Max Planck Institute
    • Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany
    • Max Planck Inst Structure & Dynamics of Matter
    • Max Planck Institue for the Structure and Dynamics of Matter
    • Theory, Max Planck Institute for the Structure & Dynamics of Matter

  • Michael Sentef

    • Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany
    • Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany
    • Max Planck Inst Structure & Dynamics of Matter
    • Max Planck Institute for the Structure and Dynamics of Matter

  • Philipp Werner

    • University of Fribourg
    • Department of Physics, University of Fribourg
    • Physics, University of Fribourg

  • Thomas Devereaux

    • Stanford Univ
    • Materials Science and Engineering, Stanford University
    • Stanford University
    • SLAC National Accelerator Laboratory
    • Photon Sciences, Stanford Linear Accelerator (SLAC)
    • SIMES, SLAC
    • Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
    • SLAC National Accelerator Lab.