Effect of Majorana Fermions on Andreev Spectroscopy of Multiband Topological Superconductors

Abstract

We introduce a model for a multiband topological superconductor with two orbitals per lattice site, in two spatial dimensions. Concentrating on the Andreev re ection problem, the appropriate wave function matching conditions for an interface with a normal single-band metal were previously derived in the framework of a quantum waveguide theory. This theory retrieves the correct number of Majorana fermion states as predicted by the topological index. We obtain the di erential conductance as a function of bias voltage, which displays the contribution of the Majorana fermions. Interface disorder is also considered. By varying band structure parameters, topological transitions can be induced, whereby the number of the Majorana modes varies. We calculate the e ect of such transitions on the di erential conductance.