Peak effect and dynamic melting of vortex matter in NbSe$_2$ crystals

TL;DR

This study investigates the vortex matter in NbSe2 crystals, revealing a dynamic melting transition and the relationship between peak effect and thermal melting through mode locking phenomena.

Contribution

It demonstrates the use of mode locking to trace shear rigidity and identify a dynamic melting transition in vortex matter near the peak effect regime.

Findings

Observation of mode locking phenomena in vortex matter.

Identification of velocity-dependent dynamic melting transition.

Revealed crossover between disorder-induced and thermally induced transitions.

Abstract

We present a mode locking (ML) phenomenon of vortex matter observed around the peak effect regime of 2H-NbSe$_2$ pure single crystals. The ML features allow us not only to trace how the shear rigidity of driven vortices persists on approaching the second critical field, but also to demonstrate a dynamic melting transition of driven vortices at a given velocity. We observe the velocity dependent melting signatures in the peak effect regime, which reveal a crossover between the disorder-induced transition at small velocity and the thermally induced transition at large velocity. This uncovers the relationship between the peak effect and the thermal melting.