Vortex core shrinking and charge oscillation effects in multi-layered superconductors

We investigate the vortex core shrinking effect in three-layered superconductors based on the inter-layer coupling Bogoliubov de Gennes (BdG) equations. It is found that the vortex core contraction is due to the quasiparticle interference effect. We point out that a rapid vortex core contraction is controlled by inter-layer couplings and a magnetic field. We also find that the quasiparticle interference effect in the vortex induces vortex charges which show an oscillation behavior. This oscillation behavior explains the local density of states (LDOSs) oscillation found in experiments.