Charge and Spin Transports Through a Normal Lead Coupled to an S‐Wave Superconductor and Majorana Fermions

Abstract

Charge and spin transports through a normal lead coupled to an s‐wave superconductor and Majorana fermions at the ends of the nanowire are investigated using the Green's function method. In the limit of the superconducting gap , the analytical expressions of charge conductance and spin conductance are obtained at zero temperature. For different values of coupling constant x between the normal lead and s‐wave superconductor, the impacts of Majorana fermions coupling energy ε m, temperature kT, and superconducting gap Δ on charge conductance and spin conductance are discussed. As x increases, changes from peak to valley and then to peak at bias ε m. The conductance of peaks and valleys is equal to quantum conductance , which corresponds to Majorana fermions. Moreover, decreases as x increases. For , the charge (spin) conductance of peaks and valleys cannot reach π . These results can help probe and understand Majorana fermions in experiments.