Experimental observation of phonon- and band-specific electron-phonon coupling in a topological semi-metal

ORAL

Abstract

Light excitation of quantum materials can drive phase transitions such as insulator-to-metal transitions or the melting of magnetic orders. It can also lead to ultrafast topological phase transitions, as it was demonstrated recently in the topological semi-metal WTe2 using ultrafast electron diffraction [1]. The photoinduced transition in this system occurs when a shear phonon mode is driven sufficiently strongly to recover the inversion symmetry of the lattice. In this context we studied the electron dynamics of WTe2 using time- and angle-resolved photoemission spectroscopy. We report the observation of band oscillations at four different frequencies that are due to A1g coherent phonon modes and include the shear mode causing the photoinduced topological transition. By isolating the effect of each phonon on the different electronic bands, we reveal the complexity of electron-phonon coupling in the electronic band structure.

[1] E. J. Sie, et al. Nature 565, 61 (2019).

*This work was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division. N.G. acknowledges support from the Swiss National Foundation (Fellowship No. P2EZP2 178542).

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Presenters

  • Nicolas Gauthier

    • Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory
    • SIMES, SLAC - Natl Accelerator Lab

Authors

  • Nicolas Gauthier

    • Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory
    • SIMES, SLAC - Natl Accelerator Lab

  • Hadas Soifer

    • School of Physics and Astronomy, Tel Aviv University

  • Alexandre Gauthier

    • Geballe Laboratory for Advanced Materials, Stanford University

  • Edbert Jarvis Sie

    • Stanford Univ
    • Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory

  • Aaron Lindenberg

    • Stanford Univ
    • Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory
    • SLAC National Accelerator Laboratory

  • Patrick Kirchmann

    • Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory
    • SIMES, SLAC - Natl Accelerator Lab

  • Zhixun Shen

    • Standford
    • Stanford University
    • Stanford Univeristy
    • Applied Physics, Stanford University
    • SLAC National Accelerator Laboratory
    • Geballe Laboratory for Advanced Materials, Department of Applied Physics, Stanford University
    • Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
    • Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory
    • SIMES, SLAC - Natl Accelerator Lab
    • Stanford Univ