Disordered vortex matter out of equilibrium: a Langevin molecular dynamics study

TL;DR

This study uses Langevin molecular dynamics to explore the non-equilibrium behavior of disordered vortex matter in high-temperature superconductors, revealing steady-state and relaxation phenomena influenced by disorder and external perturbations.

Contribution

It applies a discretized elastic line model to analyze vortex dynamics under realistic conditions, highlighting non-equilibrium steady states and glassy relaxation processes.

Findings

Current-voltage characteristics in disordered vortex matter

Observation of complex relaxation and glassy dynamics

Impact of quenches on vortex behavior

Abstract

We discuss the use of Langevin molecular dynamics in the investigation of the non-equilibrium properties of disordered vortex matter. Our special focus is set on values of system parameters that are realistic for disordered high-$T_c$ superconductors such as YBCO. Using a discretized elastic line model, we study different aspects of vortices far from thermal equilibrium. On the one hand we investigate steady-state properties of driven magnetic flux lines in a disordered environment, namely the current-voltage characteristics, the gyration radius, and the pinning time statistics. On the other hand we study the complex relaxation processes and glassy-like dynamics that emerge in type-II superconductors due to the intricate competition between the long-range vortex-vortex repulsion and flux pinning due to randomly placed point defects. To this end we consider different types of sudden perturbations: temperature, magnetic field, and external current quenches.