Low-Temperatures Vortex Dynamics in Twinned Superconductors

TL;DR

This paper investigates the low-temperature behavior of magnetic flux lines in twinned superconductors, revealing regimes dominated by superkink excitations and the impact of rare regions on flux transport.

Contribution

It introduces a detailed analysis of vortex dynamics in twinned superconductors, highlighting the role of superkink excitations and rare regions in flux transport at low temperatures.

Findings

Superkink excitations lead to Mott VRH-like flux motion.

Rare regions can significantly impede flux transport in long samples.

Mesoscopic effects arise due to rare events in short samples.

Abstract

We discuss the low-temperature dynamics of magnetic flux lines in samples with a family of parallel twin planes. A current applied along the twin planes drives flux motion in the direction transverse to the planes and acts like an electric field applied to {\it one-dimensional} carriers in disordered semiconductors. As in flux arrays with columnar pins, there is a regime where the dynamics is dominated by superkink excitations that correspond to Mott variable range hopping (VRH) of carriers. In one dimension, however, rare events, such as large regions void of twin planes, can impede VRH and dominate transport in samples that are sufficiently long in the direction of flux motion. In short samples rare regions can be responsible for mesoscopic effects.