| Drift velocity and temporal phase fluctuations of sliding charge density waves in Rb0.3MoO3 (1990) | |||||||||||||||
Abstract | |||||||||||||||
| The dynamics of CDW-s depinned by an electric field is investigated by transport, voltage noise and NMR measurements on a Rb0.3MoO 3 single crystal. A direct measurement of the bulk winding rate ν d of the sliding CDW phase is provided by the observation of sidebands in the motionally narrowed NMR spectra and by the oscillations of the spin echo amplitude as a function of the delay time. Comparison with the noise spectra confirms our earlier statement that νd is equal to the voltage noise frequency νn with an accuracy of 10 %. Experimental NMR spectra at a field of E/ET ~ 20 (ET is the depinning threshold) in the temperature range of 40 to 60 K have been fitted with high accuracy to lineshapes calculated under the assumption that the noise spectrum is related to the spatial current distribution in a simple way. Most of the experiments can be interpreted by considering the crystal as a collection of domains. In each domain the current is coherent for long times, we found in some cases a temporal coherence of 25-50 oscillation periods of the hyperfine field. We discuss stochastic variations of the CDW phase which become important at high temperatures, especially at fields near threshold. | |||||||||||||||
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