Kosterlitz-Thouless transition and radiation defects in a superconducting thin film

The thermodynamics of a system of Pearl vortices in a superconducting thin film containing radiation defects is studied. It is shown that three phase transition scenarios are possible, depending on the defect density. At low densities there is one stable state of the system. When the first critical density nd1 is reached, there appears a temperature interval in which the system can be in two stable states. If the density exceeds nd2, then the lower limit of stability of the metastable states shifts abruptly to zero.