Anomalous vortex motion in the quantum-liquid phase of amorphous MoxSi1-x films -: art. no. 047003

We measure, in real time (t), the fluctuating component of the flux-flow voltage V(t), deltaV(t)equivalent toV(t)-V-0, about the average V-0 in the vortex-liquid phase of amorphous MoxSi1-x films. For the thick film, deltaV(t) originating from the vortex motion is clearly visible in the quantum-liquid phase, where the distribution of deltaV(t) is asymmetric, indicative of large velocity and/or number fluctuations of driven vortices. For the thin film the similar anomalous vortex motion is observed in nearly the same (reduced-)temperature regime. These results suggest that vortex dynamics in the low-temperature liquid phase of thick and thin films is dominated by common physical mechanisms, presumably related to quantum effects.