Spin polarised quantised transport via one-dimensional nanowire-graphene contacts

TL;DR

This paper demonstrates ballistic spin-polarized transport in graphene using one-dimensional magnetic nanowire contacts, showing quantized conductance and quantum Hall effects without constricting the graphene channel, advancing spintronic device capabilities.

Contribution

It provides the first experimental evidence of ballistic spin injection in graphene via nanowire contacts, enabling quantum transport phenomena in spintronics.

Findings

Observation of quantised conductance without magnetic field

Transition into quantum Hall regime with increasing magnetic field

Ballistic injection of spin-polarised carriers through nanowire-graphene interface

Abstract

Graphene spintronics offers a promising route to achieve low power 2D electronics for next generation classical and quantum computation. As device length scales are reduced to the limit of the electron mean free path, the transport mechanism crosses over to the ballistic regime. However, ballistic transport has yet to be shown in a graphene spintronic device, a necessary step towards realising ballistic spintronics. Here, we report ballistic injection of spin polarised carriers via one-dimensional contacts between magnetic nanowires and a high mobility graphene channel. The nanowire-graphene interface defines an effective constriction that confines charge carriers over a length scale smaller than that of their mean free path. This is evidenced by the observation of quantised conductance through the contacts with no applied magnetic field and a transition into the quantum Hall regime with increasing field strength. These effects occur in the absence of any constriction in the graphene itself and occur across several devices with transmission probability in the range T = 0.08 - 0.30.