Superconducting/ferromagnetic diffusive bilayer with a spin-active interface: a numerical study

TL;DR

This study numerically investigates how spin-active interfaces influence the density of states in superconducting/ferromagnetic bilayers, revealing that SDIPS can induce a double gap structure even in thick superconductors.

Contribution

It introduces a self-consistent numerical approach to analyze the impact of SDIPS on the DOS and superconducting gap in S/F bilayers, highlighting the emergence of a double gap structure.

Findings

SDIPS induces a double gap structure in the DOS.

Double gap structure appears even with thick superconducting layers.

DOS curves resemble those in prior experimental studies.

Abstract

We calculate the density of states (DOS) in a diffusive superconducting/ferromagnetic bilayer with a spin-active interface. We use a self-consistent numerical treatment to make a systematic study of the effects of the Spin-Dependence of Interfacial Phase Shifts (SDIPS) on the self-consistent superconducting gap and the DOS. Strikingly, we find that the SDIPS can induce a double gap structure (DGS) in the DOS of the ferromagnet, even when the superconducing layer is much thicker than the superconducting coherence lenght. We thus obtain DOS curves which have interesting similarities with those of Phys. Rev. Lett. 100, 237002 (2008).