Valley and spin polarization from graphene line defect scattering

TL;DR

This paper presents quantum transport calculations showing that a graphene line defect can produce valley and spin polarization in transmitted electrons, with magnetic moments influencing spin but not valley polarization.

Contribution

It introduces a detailed scattering model including magnetic moments near the defect, revealing their limited impact on valley polarization but some effect on spin polarization.

Findings

Valley polarization remains robust despite magnetic moments.

Magnetic moments induce up to 20% spin polarization.

Transmission probability depends on valley, spin, and incident angle.

Abstract

Quantum transport calculations describing electron scattering off an extended line defect in graphene are presented. The calculations include potentials from local magnetic moments recently predicted to exist on sites adjacent to the line defect. The transmission probability is derived and expressed as a function of valley, spin, and angle of incidence of an electron at the Fermi level being scattered. It is shown that the previously predicted valley polarization in a beam of transmitted electrons is not significantly influenced by the presence of the magnetic moments. These moments, however, do introduce some spin polarization, in addition to the valley polarization, albeit no more than about 20%.