Tunneling characteristics of a chain of Majorana bound states

Abstract

We consider theoretically tunneling characteristic of a junction between a normal metal and a chain of coupled Majorana bound states generated at crossings between topological and nontopological superconducting sections, as a result of, for example, disorder in nanowires. While an isolated Majorana state supports a resonant Andreev process, yielding a zero-bias differential conductance peak of height $2{e}^{2}/h$, the situation with more coupled Majorana states is distinctively different with both zeros and $2{e}^{2}/h$ peaks in the differential conductance. We derive a general expression for the current between a normal metal and a network of coupled Majorana bound states and describe the differential conductance spectra for a generic set of situations, including regular, disordered, and infinite chains of bound states.