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arXiv · 1203.4488

Transport spectroscopy of NS nanowire junctions with Majorana fermions

Elsa Prada·Pablo San-Jose·Ramon Aguado
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Abstract

We investigate transport though normal-superconductor nanowire junctions in the presence of spin-orbit coupling and magnetic field. As the Zeeman field crosses the critical bulk value B_c of the topological transition, a Majorana bound state (MBS) is formed, giving rise to a sharp zero-bias anomaly (ZBA) in the tunneling differential conductance. We identify novel features beyond this picture in wires with inhomogeneous depletion, like the appearance of two MBSs inside a long depleted region for B<B_c. The resulting ZBA is in most cases weakly split and may coexist with Andreev bound states near zero energy. The ZBA may appear without evidence of a topological gap closing. This latter aspect is more evident in the multiband case and stems from a smooth pinch-off barrier. Most of these features are in qualitative agreement with recent experiments [Mourik et al, Science 336, 1003 (2012)]. We also discuss the rich phenomenology of the problem in other regimes which remain experimentally unexplored.

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Elsa Prada, Pablo San-Jose, Ramon Aguado. 2012-11-13. Transport spectroscopy of NS nanowire junctions with Majorana fermions. https://doi.org/10.1103/physrevb.86.180503

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