Square vortex lattices for two component superconducting order parameters

TL;DR

This paper analyzes the vortex lattice structures in a two-component superconductor model, revealing various lattice phases with the square lattice being most stable, and discusses implications for Sr$_2$RuO$_4$.

Contribution

It provides a detailed phase diagram of vortex lattices in a two-component superconductor and highlights the stability of the square vortex lattice.

Findings

Square vortex lattice has the largest stability region.

Vortex lattice phases include hexagonal, rectangular, and square.

Field distribution near Hc2 is characterized.

Abstract

I investigate the vortex lattice structure of the Ginzburg Landau free energy for a two component order parameter in the weak-coupling clean-limit when the field is along the high symmetry axis in a tetragonal crystal. It is shown that the vortex lattice phase diagram as a function of the Ginzburg Landau free energy parameters includes phases with a hexagonal, centered rectangular, rectangular, and square unit cells. It is also shown that the square vortex lattice has the largest region of stability. The field distribution of the square vortex lattice near $H_{c2}$ is determined and the application of this model to Sr$_2$RuO$_4$ is discussed.