The Effect of Columnar Disorder on the Superconducting Transition of a Type-II Superconductor in Zero Applied Magnetic Field

TL;DR

This study uses numerical simulations to explore how random columnar disorder influences the superconducting transition in a type-II superconductor without an external magnetic field, revealing anisotropic scaling and different dynamic critical behaviors.

Contribution

It demonstrates that columnar disorder affects the universality class and anisotropic scaling of the superconducting transition in both unscreened and screened models.

Findings

Correlation length exponent ν=1.2±0.1

Anisotropy exponent ζ=1.3±0.1

Different dynamic critical exponents for models

Abstract

We investigate the effect of random columnar disorder on the superconducting phase transition of a type-II superconductor in zero applied magnetic field using numerical simulations of three dimensional XY and vortex loop models. We consider both an unscreened model, in which the bare magnetic penetration length is approximated as infinite, and a strongly screened model, in which the magnetic penetration length is of order the vortex core radius. We consider both equilibrium and dynamic critical exponents. We show that, as in the disorder free case, the equilibrium transitions of the unscreened and strongly screened models lie in the same universality class, however scaling is now anisotropic. We find for the correlation length exponent $\nu=1.2\pm 0.1$, and for the anisotropy exponent $\zeta=1.3\pm 0.1$. We find different dynamic critical exponents for the unscreened and strongly screened models.