Transient electrical response ofK0.30MoO3

Abstract

The "blue bronze," ${\mathrm{K}}_{0.30}$Mo${\mathrm{O}}_{3}$, has been shown to have a charge-density wave (CDW) and a nonlinear dc response similar to that of Nb${\mathrm{Se}}_{3}$. We find ${\mathrm{K}}_{0.30}$Mo${\mathrm{O}}_{3}$ also shows a transient response which is qualitatively identical with that of Nb${\mathrm{Se}}_{3}$. If a current pulse drives the voltage through the threshold electric field for CDW depinning, an extremely slow voltage response is observed. The characteristic time of the slow response is proportional to the duration of the current pulse and for long pulses the voltage $V(t)\ensuremath{-}V(\ensuremath{\infty})$ is proportional to ---$\mathrm{ln}t$. In this sense the transient electrical response of ${\mathrm{K}}_{0.30}$Mo${\mathrm{O}}_{3}$ is very similar to the magnetic response of a spin-glass. These results suggest that the CDW state of materials with moving CDW's may be described by large, weakly coupled domains.