Tunneling characteristic of a chain of Majorana bound states

TL;DR

This paper theoretically analyzes the tunneling conductance in a junction between a normal metal and a chain of coupled Majorana bound states, revealing complex spectral features beyond the isolated Majorana case.

Contribution

It derives a general expression for tunneling current and conductance spectra for networks of coupled Majorana states, including disordered and infinite chains.

Findings

Presence of both zero and 2e^2/h peaks in conductance spectra.

Distinct conductance features for regular, disordered, and infinite chains.

General formula applicable to various chain configurations.

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 non-topological 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 2e^2/h, the situation with more coupled Majorana states is distinctively different with both zeros and 2e^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.