Critical Behavior of Frustrated Josephson Junction Arrays with Bond Disorder

TL;DR

This study investigates the scaling behavior and critical phenomena of frustrated Josephson junction arrays with bond disorder, revealing continuous phase transitions with unique critical exponents different from classical models.

Contribution

It provides new insights into how bond disorder influences phase transitions in frustrated Josephson junction arrays, challenging previous Monte Carlo simulation results.

Findings

Bond disorder can induce continuous phase transitions in frustrated JJA.

Critical exponent ν suggests non-Ising universality class.

Dynamic critical exponent z found to be between 0.60 and 0.77.

Abstract

The scaling behavior of the current-voltage ($IV$) characteristics of a two-dimensional proximity-coupled Josephson junction array (JJA) with quenched bond disorder was investigated for frustrations $f=1/5$, 1/3, 2/5, and 1/2. For all these frustrations including 1/5 and 2/5 where a strongly first-order phase transition is expected in the absence of disorder, the $IV$ characteristics exhibited a good scaling behavior. The critical exponent $\nu$ indicates that bond disorder may drive the phase transitions of frustrated JJA's to be continuous but not into the Ising universality class, contrary to what was observed in Monte Carlo simulations. The dynamic critical exponent $z$ for JJA's was found to be only 0.60 - 0.77.