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arXiv · 2306.05777

Ultrafast melting of charge-density wave fluctuations at room temperature in ${1T-TiSe_2}$ monitored under non-equilibrium conditions

Yu Mizukoshi·Takumi Fukuda·Yuta Komori·Ryo Ishikawa·Keiji Ueno·Muneaki Hase
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Abstract

We investigate the ultrafast lattice dynamics in ${1T-TiSe_2}$ using femtosecond reflection pump-probe and pump-pump-probe techniques at room temperature. The time-domain signals and Fourier-transformed spectra show the $A_{1g}$ phonon mode at 5.9 THz. Moreover, we observe an additional mode at $\approx$ 3 THz, corresponding to the charge-density wave (CDW) amplitude mode, which is generally visible below T$_c \approx 200\ $K. We argue that the emergence of the CDW amplitude mode at room temperature can be a consequence of fluctuations of order parameters, based on the additional experiment using the pump-pump-probe technique, which exhibited suppression of the AM signal within the ultrafast time scale of $\sim$ 0.5 ps.

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Yu Mizukoshi, Takumi Fukuda, Yuta Komori, Ryo Ishikawa, Keiji Ueno, Muneaki Hase. 2023-06-09. Ultrafast melting of charge-density wave fluctuations at room temperature in ${1T-TiSe_2}$ monitored under non-equilibrium conditions. https://doi.org/10.1063/5.0153161

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