Ultrafast x-ray scattering reveals composite amplitude collective mode in the Weyl charge density wave material (TaSe₄)₂I

2022/10/31 by Quynh L. Nguyen, Ryan A. Duncan, Nguyen, Quynh L. +57 · 1 citation
Earth and Planetary Sciences · Materials Science · #FOS: Physical sciences #High-pressure geophysics and materials #Materials Science (cond-mat.mtrl-sci) #Organic and Molecular Conductors Research #Solid-state spectroscopy and crystallography

paper · pdf · doi:10.48550/arxiv.2210.17483

openalex publication_date 2022/10/31 · openalex created_date 2022/11/06 · openalex updated_date 2026/07/28

Abstract

We report ultrafast x-ray scattering experiments of the quasi-1D charge density wave (CDW) material (TaSe₄)₂I following photoexcitation with femtosecond infrared laser pulses. From the time-dependent diffraction signal at the CDW sidebands we identify an amplitude mode derived primarily from the transverse acoustic component of the CDW static distortion. The dynamics of this acoustic amplitude mode are described well by a model of a displacive excitation, which we interpret as mediated through a coupling to the optical phonon component associated with the tetramerization of the Ta chains.

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