We study the response of the one-dimensional charge density wave in K0.3MoO3 to different types of excitation with femtosecond optical pulses. We compare the response to direct excitation of the lattice at mid-infrared frequencies with that to the injection of quasi-particles across the low-energy charge density wave gap and to charge transfer excitations in the near infrared. For all three cases, we observe a fluence threshold above which the amplitude-mode oscillation frequency is softened and the mode becomes increasingly damped. We show that all the data can be collapsed onto a universal curve in which the melting of the charge density wave occurs abruptly at a critical lattice excursion. These data highlight the existence of a universal stability limit for a charge density wave, reminiscent of the empirical Lindemann criterion for the stability of a crystal lattice.
Cite
@article{arxiv.1702.05897,
title = {A dynamical stability limit for the charge density wave in K0.3MoO3},
author = {Roman Mankowsky and Biaolong Liu and Srivats Rajasekaran and Haiyun Liu and Daixiang Mou and X. J. Zhou and Roberto Merlin and Michael Först and Andrea Cavalleri},
journal= {arXiv preprint arXiv:1702.05897},
year = {2017}
}