Simple Ginzburg-Landau theory for vortex lattice transformations in fourfold symmetric superconductors

We use a simple phenomenological model introduced by Yeo and Moore to study the vortex lattice structural transformation in the presence of fourfold symmetric coupling to an underlying lattice as in borocarbide superconductors. We focus on the aspects of the model that were not previously exploited, including the calculations of the transition line between the rhombic and the square vortex lattice phases and of the critical exponent describing the transition. We also find that, when the model parameter is interpreted appropriately, the model is consistent with the reentrant transition behavior of te vortex lattice observed in recent experiments