title: Ultrafast collective dynamics in the charge-density-wave conductor K(0.3)MoO(3).
abstract: Low-energy coherent charge-density wave excitations are investigated in blue bronze (K(0.3)MoO(3)) and red bronze (K(0.33)MoO(3)) by femtosecond pump-probe spectroscopy. A linear gapless, acousticlike dispersion relation is observed for the transverse phasons with a pronounced anisotropy in K(0.33)MoO(3). The amplitude mode exhibits a weak (opticlike) dispersion relation with a frequency of 1.67 THz at 30 K. Our results show for the first time that the time-resolved optical technique provides momentum resolution of collective excitations in strongly correlated electron systems.
authors.affiliation: Department of Applied Science, College of William and Mary, Williamsburg, Virginia 23187, USA.
authors.forename: Yuhang
authors.initials: Y
authors.lastname: Ren
authors.forename: Zhu'an
authors.initials: Z
authors.lastname: Xu
authors.forename: Gunter
authors.initials: G
authors.lastname: Lupke