Critical current from dynamical boundary instability for fully frustrated Josephson junction arrays

TL;DR

This paper numerically studies the critical current in fully frustrated Josephson junction arrays, revealing a domino-type vortex motion mechanism that influences the critical current and can be observed experimentally.

Contribution

It identifies a domino-type boundary instability mechanism responsible for the critical current being lower than flux lattice predictions in Josephson arrays.

Findings

Domino mechanism causes lower critical current than flux lattice models.

Inhomogeneities near contacts increase the critical current.

Voltage pulses from contacts indicate domino vortex motion.

Abstract

We investigate numerically the critical current of two-dimensional fully frustrated arrays of resistively shunted Josephson junctions at zero temperature. It is shown that a domino-type mechanism is responsible for the existence of a critical current lower than the one predicted from the translationally invariant flux lattice. This domino mechanism is demonstrated for uniform-current injection as well as for various busbar conditions. It is also found that inhomogeneities close to the contacts makes it harder for the domino propagation to start, which increases the critical current towards the value based on the translational invariance. This domino-type vortex motion can be observed in experiments as voltage pulses propagating from the contacts through the array.