Fano resonance in a normal metal/ferromagnet-quantum dot-superconductor device

摘要

We investigate theoretically the Andreev transport through a quantum dot strongly coupled with a normal metal/ferromagnet and a superconductor (N/F-QD-S), in which the interplay between the Kondo resonance and the Andreev bound states (ABSs) has not been clearly clarified yet. Here we show that the interference between the Kondo resonance and the ABSs modifies seriously the line shape of the Kondo resonance, which manifests as a Fano resonance. The ferromagnetic lead with spin polarization induces an effective field, which leads to splitting of both the Kondo resonance and the ABSs. The spin polarization together with the magnetic field applied provides an alternative way to tune the line shape of the Kondo resonances, which is dependent of the relative positions of the Kondo resonance and the ABSs. These results indicate that the interplay between the Kondo resonance and the ABSs can significantly affect the Andreev transport, which could be tested by experiments.