Vortex Lattice Structural Transitions: a Ginzburg-Landau Model Approach

TL;DR

This paper models the phase transition between rhombic and square vortex lattices in anisotropic superconductors using a Ginzburg-Landau approach, revealing a reentrant transition influenced by thermal fluctuations.

Contribution

It introduces a Ginzburg-Landau based framework to analyze vortex lattice transitions, including thermal fluctuation effects, providing a new theoretical perspective.

Findings

Reentrant rhombic to square lattice transition line due to thermal fluctuations

Mean-field phase diagram showing reorientation transition

Elastic moduli derived for vortex lattices

Abstract

We analyze the rhombic to square vortex lattice phase transition in anisotropic superconductors using a variant of Ginzburg-Landau (GL) theory. The mean-field phase diagram is determined to second order in the anisotropy parameter, and shows a reorientation transition of the square vortex lattice with respect to the crystal lattice. We then derive the long-wavelength elastic moduli of the lattices, and use them to show that thermal fluctuations produce a reentrant rhombic to square lattice transition line, similar to recent studies which used a nonlocal London model.