Paper
Statistics of the vortex pinning potential in superconducting films
Authors
Matvei S. Kniazev, Nikolai A. Stepanov, Mikhail A. Skvortsov
Abstract
We investigate the statistical properties of the vortex pinning potential in a thin superconducting film. Modeling intrinsic inhomogeneities by a random-temperature Ginzburg-Landau functional with short-range Gaussian disorder, we derive the pinning landscape by determining how the vortex core adapts to randomness. Within the hard-core approximation, applicable for weak disorder, the energy landscape exhibits Gaussian statistics. In this regime, the mean areal density of its minima is given by , indicating that the typical spacing between neighboring minima is significantly larger than the vortex core size . Going beyond the hard-core approximation, we allow the vortex order parameter to relax in response to the inhomogeneities. As a result, the pinning potential statistics become non-Gaussian. We calculate the leading correction due to the core deformation, which reduces the density of minima with a relative magnitude scaling as .