Anomalous flux-flow dynamics in layered type-II superconductors at low temperatures

Abstract

Low-temperature dissipation due to vortex motion in strongly anisotropic type-II superconductors with a moderate disorder ($Δ^2/E_F \ll \hbar/τ\ll Δ$) is shown to be determined by the Zener-type transitions between the localized electronic states in the vortex core. Statistics of these levels is described by the random matrix ensemble of the class C defined recently by Atland and Zirnbauer [cond-mat/9602137], so the vortex motion leads naturally to the new example of a parametric statistics of energy levels. The flux-flow conductivity $σ_{xx}$ is a bit lower than the quasiclassical one and {\it grows} slowly with the increase of the electric field.

4 pages, Revtex