Rashba spin-orbit interaction in graphene armchair nanoribbons

TL;DR

This paper investigates how Rashba spin-orbit interaction affects the electronic spectra and spin polarization in graphene nanoribbons with armchair edges, highlighting potential applications in spintronics.

Contribution

It provides a detailed analysis of RSOI effects on GNR spectra and spin polarization, including a linearized Hamiltonian approximation for practical modeling.

Findings

Spin polarization reverses sign with momentum reversal under strong RSOI.

A linear approximation captures essential RSOI effects with neighboring modes.

GNRs with armchair edges are promising for spintronics applications.

Abstract

We study graphene nanoribbons (GNRs) with armchair edges in the presence of Rashba spin-orbit interaction (RSOI). We impose the boundary conditions on the tight binding Hamiltonians for bulk graphene with RSOI by means of a sine transform and study in detail the influence of RSOI on the spectra and the spin polarization. We show that the spin polarization perpendicular to the GNR changes sign when reversing the momentum along the GNR if the bands are coupled by strong RSOI. Furthermore, we derive a linearized approximation to the RSOI Hamiltonian and find that only the neighboring modes of an energy band have to be taken into account in order to achieve a good approximation for the same band. Due to their experimental availability and various proposals for engineering appropriate RSOI, GNRs with armchair edges are a promising candidate for possible spintronics applications.