Quasi-particle spectrum of giant vortex states in a square nanoscopic superconducting plate

We have investigated quasi-particle structure and superconducting state of the nano-scaled superconductor under an external magnetic field using a microscopic Bogoliubov-de Gennes equation. Our results show that the giant vortex state has a peak of local density of states at the center of the vortex core in negative energy, while the singly quantized vortex has it in positive energy. This may be observable for scanning tunneling spectroscopy experiments.