1208.6298 (T. D. Stanescu et al.)

Disentangling Majorana fermions from conventional zero energy states in
semiconductor quantum wires    [PDF]

T. D. Stanescu, Sumanta Tewari

A proposed signature for the Majorana zero-energy quasiparticle predicted to occur in semiconductor nanowires proximity-coupled to an s-wave superconductor is the zero-bias conductance peak (ZBCP) for tunneling into the end of the wire. Recently, it has been shown that, in the presence of a smooth confining potential, nearly ZBCPs can occur even in the topologically trivial phase. Here we show that, for a smooth confinement, the emergence of the nearly ZBCP at Zeeman fields corresponding to the topologically trivial phase is necessarily accompanied by a gap closing signature in the end-of-wire local density of state (LDOS). A similar behavior is found for nearly ZBCPs that appear in the presence of strong disorder. Our results strengthen the identification of the ZBCP observed in the recent Delft measurements, which show no gap-closing signatures, with topological Majorana fermions localized at the ends of the wire.

View original: http://arxiv.org/abs/1208.6298