Quantum states and vortex patterns in nanosuperconductors

The quanum levels and corresponding vortex states in nanoscale superconductors are investigated within generalized Bogolubov‐de Gennes theory. For symmetric (square‐shaped) samples thermodynamically stable vortex phases form symmetry‐consistent patterns and no transition to conventional Abrikosov‐like vortex patterns occurs till T=0K for sizes not exceeding 25 nm. For vorticity a giant vortex is stabilized at temperatures in the vicinity of , which transforms into a giant antivortex and four normal vortices with lowering the temperature. On the other hand, the vortex pattern for vorticity corresponds to an antivortex and four normal vortices in the whole temperature domain.