Bound states and vortex core shrinking effects in iron-based superconductors

Abstract

Quasiparticle bound states and vortex core contraction effects in iron-based superconductors are studied by solving the Bogoliubov de Gennes (BdG) equations self-consistently including pair coupling effects. We find that the appearance of quasiparticle bound states in the vortex core is controlled not only by the pair coupling effects but also by the inter-orbit coupling strength. We also point out that the rapid vortex core contraction is controlled by quasiparticle interference effects. We suggest that these results deserve more attention in analysis of vortex quasiparticle bound states and vortex core contraction effects found in scanning tunneling microscopy (STM) experiments for different iron-based superconductors.