On vortex phase of systems with pairing of spatially separated electrons and holes

The structure formed by planar vortices in a disk-shaped sample in magnetic field the two-dimensional divergence of which differs from zero is considered. The total number of vortices and the energy of a system of vortices are found as a function of external magnetic field and sample size. It is established that the vortex structure energy is proportional to the system volume and, therefore, the vortex state is a new thermodynamic phase of the investigated system (similar to Shubnikov's phase in common superconductors)