The collective modes of the charge density wave (CDW) in (TaSe<sub>4</sub>)<sub>2</sub>I studied with time-resolved x-ray scattering
POSTER
Abstract
(TaSe4)2I (TSI) is a quasi-1D charge-density-wave (CDW) material and Weyl semimetal that has attracted much recent interest due to recent claims of the experimental observation of an axionic insulator phase. We studied the CDW collective modes of TSI using time-resolved x-ray scattering at the LCLS and SACLA free electron laser (FEL) facilities. We observe sub-THz oscillations at the CDW sidebands, and assign a component at 0.11 THz as an amplitude mode of the CDW. We analyze the amplitude mode signal with a coupled-mode Ginzburg-Landau model and find excellent agreement with experiment. In addition to the amplitude mode signal we also observe low-frequency dispersive signal components in the vicinity of the CDW sidebands, which we interpret as signals arising from photoexcited CDW phase modes.
*This work was supported as part of Quantum Sensing and Quantum Materials (QSQM), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science. R.A.D. additionally acknowledges support from the Stanford Q-FARM Bloch Postdoctoral Fellowship in Quantum Science and Engineering.
Presenters
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Ryan A Duncan
- Stanford University