Depinning and creep motion in glass states of flux lines

TL;DR

This study uses computer simulations to analyze vortex behavior in glass states, revealing a continuous depinning transition at zero temperature and different creep motions depending on pinning strength, with implications for experimental phase boundaries.

Contribution

It provides high-accuracy critical exponents and scaling functions for depinning and creep in vortex glass states, highlighting the distinction between weak and strong pinning regimes.

Findings

Continuous depinning transition at zero temperature.

Non-Arrhenius creep motion in weak pinning.

Arrhenius law in strong pinning regimes.

Abstract

Using dynamical computer simulation we have investigated vortex matters in glass states. A genuine continuous depinning transition is observed at zero temperature, which also governs the low-temperature creep motion. With the notion of scaling, we evaluate in high accuracy critical exponents and scaling functions; we observe a non-Arrhenius creep motion for weak collective pinning where Bragg glass (BrG) is stabilized at equilibrium, while for strong pinning the well-known Arrhenius law is recovered. In both cases, a sharp crossover takes place between depinning and creep at low temperatures. The possible relation between the present results and a recent experimental observation of a second-order like phase boundary inside the BrG phase is discussed.