Transport signatures of Majorana zero modes in magnetic insulator nanowire hybrid systems*

Semiconducting nanowires with Rashba spin-orbit coupling and proximity-induced superconductivity are the forerunners as platforms to host Majorana Zero Modes (MZMs). Recent evidence of a topological transition in hybrid Rashba nanowires epitaxially coated by superconductor-magnetic insulator bilayers points to the formation of MZMs at significantly lower external magnetic fields than in conventional systems, making it experimentally viable for scaling networks of nanowires hosting MZMs. 

We employ the Keldysh non-equilibrium Green’s function (NEGF) formalism to model transport in such hybrid wires attached to metallic contacts. We find the zero bias conductance peaks (ZBCP) in the differential conductance in the topological regime consistent with the emergence of MZMs. However, this is insufficient to prove the existence of MZMs as similar signatures may be obtained from non-topological sources. We, therefore, probe the non-local conductance, which provides robust signatures of the topological transition and can probe bulk properties of the nanowire, as compared to local conductance measurements which often just probe the states adjacent to the lead. We thus demonstrate that one may find signatures of topological MZMs at smaller magnetic fields in magnetic insulator nanowire hybrid systems.