J. Phys. IV France
Volume 131, December 2005
Page(s) 121 - 122
Publié en ligne 18 janvier 2006
International Workshop on Electronic Crystals
S. Brazovskii, P. Monceau and N. Kirova
J. Phys. IV France 131 (2005) 121-122

DOI: 10.1051/jp4:2005131027

Coherent collective oscillation in the commensurate phase of the TaS3 compound

T. Minami1, Y. Toda1, 2, K. Shimatake1 and S. Tanda1

1  Department of Applied Physics, Hokkaido University, Sapporo 060-8628, Japan
2  PRESTO Japan Science and Technology Agency, Saitama 332-0012, Japan

We have investigated ultrafast carrier dynamics in a quasi-one-dimensional metal m-TaS3 by using pump-probe reflectivity measurements. The temperature dependence of transient signal reveals two critical changes at Tp = 240 K and T$_c \sim$ 100 K. Below Tc, a new low-frequency oscillation mode appears and shows a pronounced softening depending on the temperature, indicating a collective excitation connected with the commensurability of CDW phase. This soft-mode exhibits remarkable polarization anisotropy with respect to the chain direction.

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