Ginzburg-Landau theory for a p-wave Sr2RuO4 superconductor: Vortex core structure and extended London theory

Based on a two-dimensional odd-parity superconducting order parameter for S r2RuO4 with p-wave symmetry, we investigate the single vortex and vortex la ttice 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 Lo ndon theory is developed to determine the vortex lattice structure and we f ind near H-c1 a centered rectangular vortex lattice. As the field is increa sed from H-c1 this lattice continuously deforms until a square vortex latti ce is achieved. In the centered rectangular phase the field distribution, a s measurable through mu SR experiments, exhibits a characteristic two peak structure (similar to that predicted in high temperature and borocarbide su perconductors). [S0163-1829(99)02910-0].