Multiple Andreev reflections in s-wave superconductor-quantum dot- topological superconductor tunnel junctions and Majorana bound states

摘要

We calculate the current as a function of applied voltage in non-topologicals-wave superconductor-quantum dot-topological superconductor tunnel junction.We consider the type of TS which hosts two Majorana bound states (MBS) at theends of a semiconductor quantum wire or of a chain of magnetic atoms in theproximity with s-wave superconductor. We find that the $I-V$ characteristic ofsuch system in the regime of big voltages has a typical two dot shape and isornamented by peaks of multiple Andreev reflections. We also consider the otheroptions when the zero energy states are created by disorder (here by Shibastates) or by Andreev zero energy bound states at the surface of quantum dotand superconductor. The later are obtained by tuning the magnetic field to aspecific value. Unlike the last two cases the MBS $I-V$ curves are robust tochange the magnetic field. Therefore, the magnetic field dependence of thetunneling current can serve as a unique signature for the presence of a MBS.