Signatures of Majorana fermions in hybrid superconductor-semiconductor nanowire devices

TL;DR

This paper reports electrical measurements on InSb nanowires with superconductor contacts, observing zero-bias bound states under magnetic fields, providing evidence for Majorana fermions in hybrid superconductor-semiconductor nanowire devices.

Contribution

It presents experimental evidence of zero-bias bound states in InSb nanowires, supporting the existence of Majorana fermions in such hybrid systems.

Findings

Zero-bias bound states observed at magnetic fields around 100 mT

Bound states remain fixed to zero bias over varying magnetic fields and gate voltages

Supports the hypothesis of Majorana fermions in superconductor-semiconductor nanowires

Abstract

Majorana fermions are particles identical to their own antiparticles. They have been theoretically predicted to exist in topological superconductors. We report electrical measurements on InSb nanowires contacted with one normal (Au) and one superconducting electrode (NbTiN). Gate voltages vary electron density and define a tunnel barrier between normal and superconducting contacts. In the presence of magnetic fields of order 100 mT we observe bound, mid-gap states at zero bias voltage. These bound states remain fixed to zero bias even when magnetic fields and gate voltages are changed over considerable ranges. Our observations support the hypothesis of Majorana fermions in nanowires coupled to superconductors.