Majorana fermions in a tunable semiconductor device

TLDR

The experimental realization of Majorana fermions is important because of their non‑Abelian statistics and potential use in topological quantum computation, and recent work by Sau et al. shows that a topological superconducting phase can be achieved with a semiconductor quantum well coupled to an s‑wave superconductor and a ferromagnetic insulator. The authors propose an alternative setup to realize a topological superconducting phase by applying an in‑plane magnetic field to a (110)-grown semiconductor coupled only to an s‑wave superconductor. They discuss the experimental feasibility of both this in‑plane‑field configuration and the earlier Sau et al.

Abstract

The experimental realization of Majorana fermions presents an important problem due to their non-Abelian nature and potential exploitation for topological quantum computation. Very recently Sau et al. [arXiv:0907.2239] demonstrated that a topological superconducting phase supporting Majorana fermions can be realized using surprisingly conventional building blocks: a semiconductor quantum well coupled to an s-wave superconductor and a ferromagnetic insulator. Here we propose an alternative setup, wherein a topological superconducting phase is driven by applying an in-plane magnetic field to a (110)-grown semiconductor coupled only to an s-wave superconductor. This device offers a number of advantages, notably a simpler architecture and the ability to tune across a quantum phase transition into the topological superconducting state, while still largely avoiding unwanted orbital effects. Experimental feasibility of both setups is discussed in some detail.