Transverse depinning and melting of a moving vortex lattice in driven periodic Josephson junction arrays

TL;DR

This paper investigates how thermal fluctuations influence the behavior of a driven vortex lattice in a Josephson junction array, revealing depinning, melting, and transverse motion transitions as functions of current and temperature.

Contribution

It provides a detailed phase diagram of vortex lattice states, including transverse depinning and melting transitions under thermal fluctuations and applied currents.

Findings

Moving vortex lattice exhibits anisotropic Bragg peaks.

Melting transition occurs at high currents and temperatures.

Transverse depinning occurs at a temperature below melting point.

Abstract

We study the effect of thermal fluctuations in a vortex lattice driven in the periodic pinning of a Josephson junction array. The phase diagram current ($I$) vs. temperature ($T$) is studied. Above the critical current $I_c(T)$ we find a moving vortex lattice (MVL) with anisotropic Bragg peaks. For large currents $I\gg I_c(T)$, there is a melting transition of the MVL at $T_M(I)$. When applying a small transverse current to the MVL, there is no dissipation at low $T$. We find an onset of transverse vortex motion at a transverse depinning temperature $T_{tr}(I)<T_M(I)$.