Ultrafast scattering dynamics of coherent phonons in Bi1-x Sbx in the Weyl semimetal phase

Yuta Komori, Yuta Saito, Paul Fons, Muneaki Hase

Research output: Contribution to journalArticlepeer-review

Abstract

We investigate ultrafast phonon dynamics in the Bi1-x Sb x alloy system for various compositions x using a reflective femtosecond pump-probe technique. The coherent optical phonons corresponding to the A1g local vibrational modes of Bi-Bi, Bi-Sb, and Sb-Sb are generated and observed in the time domain with a few picoseconds dephasing time. The frequencies of the coherent optical phonons were found to change as the Sb composition x was varied, and more importantly, the relaxation time of those phonon modes was dramatically reduced for x values in the range 0.5-0.8. We argue that the phonon relaxation dynamics are not simply governed by alloy scattering, but are significantly modified by anharmonic phonon-phonon scattering with implied minor contributions from electron-phonon scattering in a Weyl-semimetal phase.

Original languageEnglish
Article number023034
JournalNew Journal of Physics
Volume23
Issue number2
DOIs
Publication statusPublished - 2021 Feb

Keywords

  • coherent phonon
  • phonon scattering
  • topological materials
  • ultrafast spectroscopy

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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