Critical current in charge-density wave transport

Abstract

We report transport measurements under very high current densities $j$, up to $\sim 10^8$~A/cm${}^2$, of quasi-one-dimensional charge-density wave (CDW) conductors NbSe${}_3$ and TaS${}_3$. Joule heating has been minimized by using a point-contact configuration or by measuring samples with extremely small cross-sections. Above $j_c\approx 10^7$~A/cm${}^2$ we find evidence for suppression of the Peierls gap and development of the metallic state. The critical CDW velocity corresponding with $j_0$ is comparable with the sound velocity, and with $\Delta /\hslash k_F$ ($k_F$ is the Fermi wave vector), which corresponds to the depairing current. Possible scenarios of the Peierls state destruction are discussed.

5pages, 5 figures