Ginzburg-Landau Theory for a p-Wave Sr_2RuO_4 Superconductor: Vortex Core Structure and Extended London Theory

TL;DR

This paper develops a Ginzburg-Landau and extended London theory for p-wave Sr_2RuO_4 superconductors, revealing vortex core structures and lattice transformations near the lower critical field, with implications for experimental measurements.

Contribution

It introduces a detailed theoretical framework for vortex structures in p-wave Sr_2RuO_4, including vortex lattice evolution and measurable field distribution features.

Findings

Vortex core exhibits a fourfold structure influenced by Fermi surface properties.

Vortex lattice transitions from centered rectangular to square as magnetic field increases.

Field distribution shows a two-peak structure detectable by -SR experiments.

Abstract

Based on a two dimensional odd-parity superconducting order parameter for Sr_2RuO_4 with p-wave symmetry, we investigate the single vortex and vortex lattice structure of the mixed phase near H_{c1}. Ginzburg-Landau calculations for a single vortex show a fourfold structure with an orientation depending on the microscopic Fermi surface properties. The corresponding extended London theory is developed to determine the vortex lattice structure and we find near H_{c1} a centered rectangular vortex lattice. As the field is increased from H_{c1} this lattice continuously deforms until a square vortex lattice is achieved. In the centered rectangular phase the field distribution, as measurable through \mu-SR experiments, exhibits a characteristic two peak structure (similar to that predicted in high temperature and borocarbide superconductors).