Scaling approach to pinning: Charge density waves and giant flux creep in superconductors

Abstract

A general scaling approach to pinning and response in weakly disordered systems is developed that considers pinning at arbitrary high energy barriers. These are a consequence of a disordered T=0 renormalization-group fixed point which characterizes the condensed phase. Application to flux creep in superconductors yields a creep velocity \ensuremath{\nu}(j)\ensuremath{\propto}exp-${\mathit{Cj}}^{\mathrm{\ensuremath{-}}\mathrm{\ensuremath{\mu}}}$ where \ensuremath{\mu} is related to the roughness exponents \ensuremath{\zeta} of the flux-line lattice. We argue that \ensuremath{\zeta}=0(log) and \ensuremath{\mu}=(d-2)/2 as for charge-density waves.