The ultra-high-TP charge-density wave in the monoclinic phase of NbS3.

We report on high temperature (T) studies of conductivity, σ, of the monoclinic phase of NbS 3 (NbS 3 -II). The compound is shown to be stable up to T ∼550 K. Threshold non-linear conductivity and Shapiro steps on the I – V curves can be seen up to T P0 ≈ 450 – 475 K clearly demonstrating sliding of a charge-density wave (CDW). The feature in σ(T) shows that T P0 is the temperature of the formation of this CDW. The charges condensed in this CDW show relatively high density and, at the same time, extremely low mobility. Their mobility appears low in the single-particle states as well, giving a plausible clue to the surprising dielectric-like temperature variation of σ above T P0. Image 1 • The highest temperature of a charge-density wave (CDW) transition, T P0 =450 – 475 K. • Coherent sliding of this CDW and its synchronization under rf field. • Formation of the CDW from non-metallic electronic state. • High density and extremely low mobility of charges in this CDW. • The Shapiro steps provide a way to estimate carrier mobilities above a CDW transition. • Correlation of the mobilities of charges in the condensed and single-particle states for all the three CDWs in NbS 3. [ABSTRACT FROM AUTHOR]