Scaling Universality at the Dynamic Vortex Mott Transition

TL;DR

This paper investigates the critical behavior of the dynamic vortex Mott transition in superconducting vortex systems, revealing universal scaling and a PT symmetry-breaking mechanism that links nonequilibrium and thermal phase transitions.

Contribution

It introduces a theory for the nonequilibrium vortex Mott transition based on PT symmetry-breaking, showing its critical behavior matches that of thermal Mott transitions.

Findings

Universal scaling observed with respect to current and temperature.

Critical exponent matches that of the thermodynamic Mott transition.

PT symmetry-breaking underpins the out-of-equilibrium phase transition.

Abstract

The dynamic Mott insulator-to-metal transition (DMT) is key to many intriguing phenomena in condensed matter physics yet it remains nearly unexplored. The cleanest way to observe DMT, without the interference from disorder and other effects inherent to electronic and atomic systems, is to employ the vortex Mott states formed by superconducting vortices in a regular array of pinning sites. The applied electric current delocalizes vortices and drives the dynamic vortex Mott transition. Here we report the critical behavior of the vortex system as it crosses the DMT line, driven by either current or temperature. We find universal scaling with respect to both, expressed by the same scaling function and characterized by a single critical exponent coinciding with the exponent for the thermodynamic Mott transition. We develop a theory for the DMT based on the parity reflection-time reversal (PT) symmetry breaking formalism and find that the nonequilibrium-induced Mott transition has the same critical behavior as thermal Mott transition. Our findings demonstrate the existence of physical systems in which the effect of nonequilibrium drive is to generate effective temperature and hence the transition belonging in the thermal universality class. We establish PT symmetry-breaking as a universal mechanism for out-of-equilibrium phase transitions.