Differential shot noise and Fano factor in a ferromagnet-Graphene-superconductor junction

Abstract Differential shot noise and Fano factor are investigated theoretically in a ferromagnet-Graphene-superconductor junctions, where ferromagnetism and superconductivity are induced by proximity effect, while the intermediate layer is Graphene. We have found that sub-gap region in shot noise and Fano factor is strongly affected by the ferromagnetic exchange energy. We have found that shot noise and Fano factor are suppressed when the exchange energy increases and the Andreev retro-reflection is the dominant process. When the dominant process is specular Andreev reflection, shot noise and Fano factor enhance by increasing the exchange energy. Also, for a wide intermediate Graphene layer, the shot noise oscillates vs applied bias voltage while there is no oscillation in the curves of Fano factor vs bias voltage. The calculation of Fano factor at zero bias shows that the Fano factor vs spin-polarization displays a clear distinction between Andreev retro-reflection and specular Andreev reflection. Our finding can be used not only to understand more about Andreev retro-reflection and specular Andreev reflection but also to discriminate between them through the differential shot noise and Fano factor.