Critical behavior of dynamic vortex Mott transition in superconducting arrays at fractional vortex densities

TL;DR

This study investigates the critical behavior of the dynamic vortex Mott transition in 2D superconducting arrays at fractional vortex densities, revealing scaling laws and critical exponents consistent with experiments.

Contribution

The paper provides a detailed Monte Carlo simulation analysis of vortex-induced resistivity transitions, identifying critical exponents and phase behavior at specific fractional vortex densities.

Findings

Critical exponents match experimental results near f=1/2.

Similar scaling observed at f=1/3.

Transition absent at f=1/2 in honeycomb arrays.

Abstract

We study the differential resistivity transition of two-dimensional superconducting arrays induced by an external driving current, in the presence of thermal fluctuations and a magnetic field corresponding to $f$ flux quantum per plaquette. Recent experiments have identified this transition as a dynamic vortex Mott insulator transition at vortex densities near rational values of $f$. The critical behavior is determined from a scaling analysis of the current-voltage relation near the transition, obtained by Monte Carlo simulations of a Josephson-junction array model in the vortex representation. For a square-lattice array, the critical exponents obtained near $f=1/2$ are consistent with the experimental observations. The same scaling behavior is observed near $f=1/3$. For a honeycomb array, although similar results are obtained for $f=1/3$, the transition is absent for $f=1/2$, consistent with an incommensurate vortex phase.