Current-voltage scaling of a Josephson-junction array at irrational frustration

TL;DR

This paper investigates the current-voltage behavior of a 2D Josephson junction array at irrational flux, revealing a vortex glass transition with unique critical exponents and temperature dependence of nonlinearities.

Contribution

It provides numerical evidence for a zero-temperature vortex glass transition in an ordered array at irrational flux, with distinct critical exponents from disordered models.

Findings

Vortex glass transition occurs at zero temperature.

Nonlinear current-voltage behavior decreases as T^2, not T^3.

Critical exponents differ from disordered superconductor models.

Abstract

Numerical simulations of the current-voltage characteristics of an ordered two-dimensional Josephson junction array at an irrational flux quantum per plaquette are presented. The results are consistent with an scaling analysis which assumes a zero temperature vortex glass transition. The thermal correlation length exponent characterizing this transition is found to be significantly different from the corresponding value for vortex-glass models in disordered two-dimensional superconductors. This leads to a current scale where nonlinearities appear in the current-voltage characteristics decreasing with temperature $T$ roughly as $T^2$ in contrast with the $T^3$ behavior expected for disordered models.