Vortex - antivortex configurations and their stability in mesoscopic superconducting square

Vortex-antivortex configurations and their stability in mesoscopic superconducting square. Abstract We solve the Ginzburg-Landau equation (GLE) for the mesoscopic super-conducting thin film of the square shape in the magnetic field for the wide range of the Ginzburg-Landau parameter 0.05 < κ ef f < ∞. We focus on the region of the field where formation of the antivortex has been reported previously. We found that the phase with the antivortex exists in the broad range of parameters. When the coherence length decreases the topological phase transition to the phase with the same total vorticity and a reduced symmetry takes place. The giant vortex with the vorticity m = 3 is found to be unstable for any field, ξ/a and κ ef f 0.1. Reduction of κ ef f does not make the phase with antivortex more stable contrary to the case of the cylindric sample of the type I superconductor.