Conductance Spectroscopy of Majorana Zero Modes in Superconductor-Magnetic Insulating Nanowire Hybrid Systems

TL;DR

This paper models quantum transport in superconductor-magnetic insulator nanowire systems to identify conditions for Majorana zero modes, analyzing the effects of disorder and providing insights into their experimental detection.

Contribution

It introduces a non-equilibrium Green's function model for superconductor-magnetic insulator nanowires, highlighting the impact of disorder on Majorana mode signatures.

Findings

Topological zero modes emerge with gap closing and reopening in clean systems.

Disorder can lead to trivial Andreev bound states mimicking Majorana signatures.

Transport analysis helps distinguish between topological and trivial states.

Abstract

There has been recent interest in superconductor-magnetic insulator hybrid Rashba nanowire setups for potentially hosting Majorana zero modes at smaller external Zeeman fields. Using the non-equilibrium Green's function technique, we develop a quantum transport model that accounts for the interplay between the quasiparticle dynamics in the superconductor-magnetic insulator bilayer structure and the transport processes through the Rashba nanowire. We provide an analysis of three-terminal setups to probe the local and non-local conductance in clean and disordered nanowires. We uncover the gap closing and reopening followed by the emergence of near-zero energy states, which can be attributed to topological zero modes in the clean limit. In the presence of a disordered potential, trivial Andreev bound states may form with signatures reminiscent of topological zero modes. Our results provide transport-based analysis of regimes that support the formation of Majorana modes in these hybrid systems while investigating the effect of disorder on devices.