Gigahertz-range synchronization at room temperature and other features of charge-density wave transport in the quasi-one-dimensional conductor NbS3

Whiskers of the quasi-one-dimensional conductor NbS3, phase II, have been synthesized. The samples show two charge-density wave (CDW) states: below 360 and below 150 K. Both CDWs show sharp threshold fields and coherent transport revealed by ac-dc coupling, i.e., Shapiro steps. The thinnest samples (cross sections below 10(4) nm(2)) exhibit Shapiro steps for frequencies at least as high as 4 GHz at room temperature. The results indicate that, for each of the CDW states, only one Nb chain per unit cell participates in the CDW transport.