Surface melting of the vortex lattice

TL;DR

This paper investigates how surfaces influence the melting transition of vortex lattices in layered superconductors, predicting both discontinuous and continuous surface melting with implications for experimental hysteresis observations.

Contribution

It introduces a density functional theory approach to analyze surface effects on vortex lattice melting, highlighting the dominance of continuous melting in the phase diagram.

Findings

Both discontinuous and continuous surface melting are predicted.

Continuous surface melting dominates the low-field phase diagram.

Surface effects cause asymmetric hysteresis in melting behavior.

Abstract

We discuss the effect of an (ab)-surface on the melting transition of the pancake-vortex lattice in a layered superconductor within a density functional theory approach. Both discontinuous and continuous surface melting are predicted for this system, although the latter scenario occupies the major part of the low-field phase diagram. The formation of a quasi-liquid layer below the bulk melting temperature inhibits the appearance of a superheated solid phase, yielding an asymmetric hysteretic behavior which has been seen in experiments.