Dynamic Vortex Phases and Pinning in Superconductors with Twin Boundaries

TL;DR

This study uses large-scale simulations to explore how vortices in superconductors interact with twin boundaries, revealing multiple dynamic phases and their relation to measurable electrical properties.

Contribution

It provides new insights into vortex pinning and flow phases in superconductors with twin boundaries through extensive molecular dynamics simulations.

Findings

Identification of multiple vortex flow phases with increasing drive

Correlation of dynamical phases with voltage-current characteristics

Development of vortex dynamic phase diagrams for different boundary parameters

Abstract

We investigate the pinning and driven dynamics of vortices interacting with twin boundaries using large scale molecular dynamics simulations on samples with near one million pinning sites. For low applied driving forces, the vortex lattice orients itself parallel to the twin boundary and we observe the creation of a flux gradient and vortex free region near the edges of the twin boundary. For increasing drive, we find evidence for several distinct dynamical flow phases which we characterize by the density of defects in the vortex lattice, the microscopic vortex flow patterns, and orientation of the vortex lattice. We show that these different dynamical phases can be directly related to microscopically measurable voltage - current V(I) curves and voltage noise. By conducting a series of simulations for various twin boundary parameters we derive several vortex dynamic phase diagrams.