Superconducting order parameter in layered systems

In this talk we sketch the solution of the fully relativistic spin-polarized Kohn-Sham Bogoliubov de Gennes equations for multilayers within multiple scattering theory. In this formalism the Green function and consequently various physical quantities can be calculated easily. Particularly interesting is the so called anomalous charge, as it can be related to the order parameter.
Result will be presented for the NbAu, NbFe and NbAuFe overlayer systems. We find a linear decay of the order parameter in the non-magnetic case, however, we find that the spin splitting of the electron states in the ferromagnet leads to spatial modulation of the proximity induced pair amplitudes due to Cooper pairs with a finite center of mass momentum showing oscillatory behavior similarly to the FFLO state. More interestingly, in case of the NbAuFe system we also show that the existence of spin-polarized quantum well states can lead to such oscillations of the order parameter in the normal metal.