Phase transition in site-diluted Josephson junction arrays: A numerical study

TL;DR

This study uses numerical methods to analyze how site-diluted disorder affects phase transitions in 2D Josephson-junction arrays, revealing a shift from Kosterlitz-Thouless to continuous transitions and exploring depinning and creep phenomena.

Contribution

It provides a detailed numerical investigation of disorder effects on phase transitions and creep motion in Josephson-junction arrays, clarifying the nature of these transitions.

Findings

Kosterlitz-Thouless transition is replaced by a continuous transition with power-law divergence.

Depinning transition and creep motion are characterized and distinguished.

Results align with recent experimental observations.

Abstract

We numerically investigate the intriguing effects produced by random percolative disorder in two-dimensional Josephson-junction arrays. By dynamic scaling analysis, we evaluate critical temperatures and critical exponents with high accuracy. It is observed that, with the introduction of site-diluted disorder, the Kosterlitz-Thouless phase transition is eliminated and evolves into a continuous transition with power-law divergent correlation length. Moreover, genuine depinning transition and creep motion are studied, evidence for distinct creep motion types is provided. Our results not only are in good agreement with the recent experimental findings, but also shed some light on the relevant phase transitions.