Unzipping flux lines from extended defects in type-II superconductors

TL;DR

This paper investigates the unbinding transition of flux lines from extended defects in type-II superconductors, revealing universal behavior influenced by defect dimensionality and complex dependencies on vortex interactions.

Contribution

It introduces a detailed analysis of flux line unbinding transitions considering point disorder and vortex interactions, highlighting the role of defect dimensionality and Luttinger liquid physics.

Findings

Transition universality depends on defect dimensionality.

Critical properties are influenced by the Luttinger liquid parameter.

Unbinding behavior varies with disorder and vortex density.

Abstract

With magnetic force microscopy in mind, we study the unbinding transition of individual flux lines from extended defects like columnar pins and twin planes in type II superconductors. In the presence of point disorder, the transition is universal with an exponent which depends only on the dimensionality of the extended defect. We also consider the unbinding transition of a single vortex line from a twin plane occupied by other vortices. We show that the critical properties of this transition depend strongly on the Luttinger liquid parameter which describes the long distance physics of the two-dimensional flux line array.