Ferromagnetic proximity effect in a ferromagnet/iron-pnictide superconductor junction

摘要

The proximity effect in a bilayer consisting of a ferromagnet (FM) and an iron-pnictide superconductor (SC) with antiphase s-wave pairing is first studied by extending Nambu spinor Green's function approach. Due to the opposite signs of the two pair potentials in the SC, the order parameters in the FM and SC regions at the interface induced by the proximity effect are not only noncontinuous but also antiphase and the barrier strength has a significant influence on the peak and dip behaviors of the induced superconducting density of states (DOS) in the two regions. Particularly, one conspicuously characteristic peak of the DOS at either gap energy in the SC appears. These properties are much different from those without antiphase s-wave pairing for the SC, which can be applied to experimentally identify the antiphase s-wave pairing in iron-based SCs.