Majorana bound states and zero-bias conductance peaks in superconductor/semiconductor nanowire devices

Abstract

Theoretical research suggests an emergence of the Majorana bound states at the ends of nanowires. Experimental verifications of this concept have already been executed, e.g., in superconductor/semiconductor nanowire devices where interplay between a superconducting gap, spin-orbit coupling and external magnetic field allows for the creation of zero-energy bound states. Recent experiments propose a topological phase diagram by a local modification of the effective chemical potential. We discuss this possibility, using a model of an experimental system in the form of a semi-infinite S/N junction. We calculate the zero-bias differential conductance G in the case of the homogeneous system, as well as in the presence of the gate voltage. The relation between conductance and the effective gap in the system is investigated. We show that G can reproduce the topological phase diagram in the magnetic field vs. gate voltage space of parameters.