A statistical phase-slip model capable to describe fluctuations measured in charge density-wave systems

The charge transport via motion of charge density-waves (CDW) requires a conversion of the charge carriers provided by the contacts (called single charge carriers or quasiparticles) into collective ones which are part of the CDW and vice versa. The conversion occurs via a so-called phase slip, i.e. phase fronts are added to or removed from the CDW, leading to a stress or strain in the CDW, respectively, which relaxes by a motion of the CDW. The dynamics of the conversion process has a formative influence on the time-resolved signals measured at the contacts. We introduce a phase-slip model which comprises the shape, the location, and the statistics of the intervals between successive phase-slip events and is able to describe noise phenomena often observed in CDW systems. The Fourier transform of the signal produced by a single phase-slip event deduced from the well-established Fukujama–Lee–Rice model can be identified with the broad-band noise spectrum measured in experiment. The statistics which describes the sequence of these single events determines the narrow-band noise. We compare the noise spectra gained from the model with the ones obtained from our noise measurements on o -TaS 3 samples.