Proximity effect between an unconventional superconductor and a ferromagnet with spin bandwidth asymmetry

We study the proximity effect within a junction made of an unconventional superconductor (US) and a ferromagnet (F) in the clean limit with high barrier transparency. Superconductivity in the US side is described by an extended Hubbard model with intersite attractive interaction, while metallic ferromagnetism in the F side is assumed to be originated by a relative change in the bandwidths of electrons with opposite spin. The effect of this mass-split mechanism is analyzed in conjunction with the usual Stoner-like one, where one band is rigidly shifted with respect to the other, due to the presence of a constant exchange field. Starting from the numerical solution of the Bogoliubov-de Gennes equations, we show that the two above mentioned mechanisms for ferromagnetism lead to different features as concerns the formation at the interface of dominant and subdominant superconducting components, as well as their propagation in the ferromagnetic side. This considerably affects the opening of gaplike structures in the local density of states for majority and minority spin electrons, leading to distinct effects as one moves toward the half-metallic regime, where the density of the minority carriers becomes vanishing.