Majorana modes and Fano resonances in Aharonov-Bohm ring with topologically nontrivial superconducting bridge

Abstract

We study different resonances (first of all of the Fano type) in the interference device formed by the Aharonov-Bohm ring with superconducting (SC) wire in the topologically nontrivial state playing a role of a bridge between top and bottom arms. We analyze Majorana modes on the ends of the SC wire and show that the collapse of the additional Fano resonance, that is initially induced by transport scheme asymmetry, is connected with the increase of the length of the bridge when the binding energy of the Majorana end modes tends to zero. In local transport regime, the Fano resonances are stable against the change of the transport symmetry. The reasons of both collapse and sustainability are analyzed using a spinless toy model including the Kitaev chain.