Frustrated two-dimensional Josephson junction array near incommensurability

TL;DR

This study investigates the current-voltage behavior of frustrated 2D Josephson junction arrays near incommensurability, revealing universal scaling behaviors and similar vortex configurations at various rational frustrations, which aids understanding of their superconducting transitions.

Contribution

It provides new insights into the universal scaling behaviors and vortex configurations of frustrated Josephson junction arrays near incommensurability, highlighting similarities across different rational frustrations.

Findings

Universal scaling behaviors observed at multiple frustrations

High superconducting transition temperatures near incommensurability

Similar vortex configurations across different rational frustrations

Abstract

To study the properties of frustrated two-dimensional Josephson junction arrays near incommensurability, we examine the current-voltage characteristics of a square proximity-coupled Josephson junction array at a sequence of frustrations f=3/8, 8/21, 0.382 $(\approx (3-\sqrt{5})/2)$, 2/5, and 5/12. Detailed scaling analyses of the current-voltage characteristics reveal approximately universal scaling behaviors for f=3/8, 8/21, 0.382, and 2/5. The approximately universal scaling behaviors and high superconducting transition temperatures indicate that both the nature of the superconducting transition and the vortex configuration near the transition at the high-order rational frustrations f=3/8, 8/21, and 0.382 are similar to those at the nearby simple frustration f=2/5. This finding suggests that the behaviors of Josephson junction arrays in the wide range of frustrations might be understood from those of a few simple rational frustrations.