Determination of the electron-phonon coupling with time-domain techniques reveal contrasting bond strengths in topological semimetal WTe<sub>2</sub>

ORAL

Abstract

We studied the electron and structural dynamics of the topological semimetal WTe2 using time- and angle-resolved photoemission spectroscopy (trARPES), ultrafast electron diffraction (UED) and density functional theory (DFT). We report the observation of band oscillations at multiple frequencies due to A1 coherent phonon modes. 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. Combining these spectroscopic observations with UED results, we quantify the electron-phonon coupling strength in WTe2 for two A1 phonons and find that inter-layer modes are more weakly coupled than intra-layer modes. We explain this difference with the general expectation that Van der Waals bonds are weaker than covalent bonds. Our results impact the understanding how lattice structure determines electronic and topological properties.

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

Authors

  • Nicolas Gauthier

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

  • Hadas Soifer

    • Tel Aviv University

  • Alexandre Gauthier

    • Stanford University
    • Geballe Laboratory for Advanced Materials, Stanford University

  • Idris Boukahil

    • Physics, Stanford
    • Stanford University

  • C Das Pemmaraju

    • SLAC, Stanford
    • Materials Science, SLAC National Accelerator Laboratory
    • SLAC Stanford
    • Stanford Univ
    • SLAC - Natl Accelerator Lab

  • Edbert Jarvis Sie

    • Stanford University

  • Clara M Nyby

    • Stanford University

  • Aaron Lindenberg

    • Stanford Univ
    • Stanford University

  • Patrick S Kirchmann

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

  • Zhixun Shen

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