Resonant Andreev reflection in a normal metal/quantum dot/superconductor system with coupled Majorana bound states
Andreev reflection(AR) in a normal metal/quantum dot/superconductor(N QD S) system with coupled Majorana bound states(MBSs) is investigated theoretically. We find that in the N QD S system, the AR can be enhanced when coupling to the MBSs is incorporated. Fano line shapes can be observed in the AR conductance spectrum when there is an appropriate QD MBS coupling or MBS MBS coupling. The AR conductance is always e~2/2h at the zero Fermi energy point when only QD MBSs coupling is considered. In addition, the resonant AR occurs when the MBS MBS coupling roughly equals to the QD energy level. We also find that an AR antiresonance appears when the QD energy level approximately equals to the sum of the QD MBS coupling and the MBS MBS coupling. These features may serve as characteristic signatures for the probe of MBSs.