Electron-phonon coupling in photoexcited Bi<sub>2</sub>Te<sub>3</sub>

ORAL

Abstract



Bi2Te3 is a topological insulator and thermoelectric material with a high figure-of-merit at room temperature. Strong spin-orbit coupling leads to the inversion of its bulk valence and conduction bands, which results in the formation of topologically-protected surface states [1]. Despite this protection, the surface states may be scattered by lattice vibrations [2]. Here we study the electron-phonon interaction of the surface states in Bi2Te3 using density functional theory and density functional perturbation theory. We calculate the deformation potentials of the surface states due to coupling to the coherent A1g modes driven by photoexcitation. Our computed deformation potential values agree well with those obtained from time-resolved ARPES measurements and time-resolved Bragg diffraction. Our calculations also quantitatively reproduce the experimentally observed magnitude of the surface phonon softening. These findings open opportunities for reliable first principles predictions of the topological transport properties of Bi2Te3 and related V2-VI3 materials.

[1] Y. L. Chen et al, Nature 325, 178 (2009)
[2] K. Shrestha et al, Phys. Rev. B 95, 195113 (2017)

*
This work was supported by Science Foundation Ireland under Investigators Programme No. 15/IA/3160.

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Presenters

  • Jose Querales-Flores

    • Tyndall National Institute
    • Materials Theory, Tyndall National Institute

Authors

  • Jose Querales-Flores

    • Tyndall National Institute
    • Materials Theory, Tyndall National Institute

  • Ivana Savic

    • Tyndall National Institute
    • Tyndall National Institute, Cork, Ireland
    • Materials Theory, Tyndall National Institute

  • Éamonn Murray

    • Imperial College London, UK
    • Department of Physics and Department of Materials, Imperial College London
    • Department of Materials and Department of Physics, Imperial College London

  • Stephen B Fahy

    • University College Cork
    • University College Cork, Ireland
    • Department of Physics, University College Cork
    • Department of Physics, University College Cork, Cork, Ireland
    • Materials Theory, Tyndall National Institute

  • Jonathan Sobota

    • Stanford University
    • Department of Applied Physics, Stanford University
    • SLAC National Accelerator Laboratory

  • Samuel W Teitelbaum

    • Department of Chemistry, Massachusetts Institute of Technology
    • SLAC National Accelerator Laboratory, Stanford Institute for Materials and Energy Sciences

  • Takahiro Sato

    • Stanford PULSE Institute, SLAC National Accelerator Laboratory

  • Matthieu Chollet

    • Stanford PULSE Institute, SLAC National Accelerator Laboratory

  • James M Glownia

    • SLAC National Accelerator Laboratory

  • Mariano Trigo

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

  • Trevor P Bailey

    • Department of Physics, University of Michigan

  • Ctirad Uher

    • Department of Physics, University of Michigan

  • Patrick S Kirchmann

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

  • Zhi-Xun Shen

    • Stanford University
    • SLAC National Accelerator Laboratory

  • Costel R. Rotundu

    • Department of Applied Physics, Stanford University
    • Stanford University

  • Thomas Henighan

    • Stanford University

  • David A Reis

    • Stanford University