Hole-doped semiconductor nanowire on top of an s-wave superconductor: A new and experimentally accessible system for Majorana fermions

TL;DR

This paper proposes that hole-doped semiconductor nanowires on s-wave superconductors can host Majorana fermions at lower Zeeman fields due to their strong spin-orbit coupling and effective mass, making experimental realization more feasible.

Contribution

It demonstrates that hole-doped nanowires require smaller Zeeman fields for Majorana fermions, expanding the accessible experimental parameter space compared to electron-doped systems.

Findings

Majorana fermions can be realized in hole-doped nanowires with small Zeeman fields.

Hole-doped systems have stronger spin-orbit coupling and effective mass, facilitating Majorana states.

Experimental conditions for Majorana fermions are more readily achievable in hole-doped systems.

Abstract

Majorana fermions were envisioned by E. Majorana in 1935 to describe neutrinos. Recently it has been shown that they can be realized even in a class of electron-doped semiconductors, on which ordinary s-wave superconductivity is proximity induced, provided the time reversal symmetry is broken by an external Zeeman field above a threshold. Here we show that in a hole-doped semiconductor nanowire the threshold Zeeman field for Majorana fermions can be very small for some magic values of the hole density. In contrast to the electron-doped systems, smaller Zeeman fields and much stronger spin-orbit coupling and effective mass of holes allow the hole-doped systems to support Majorana fermions in a parameter regime which is routinely realized in current experiments.