Spin Filter Properties of Armchair Graphene Nanoribbons with Substitutional Fe Atoms

TL;DR

This study demonstrates that armchair graphene nanoribbons with substitutional Fe atoms can act as effective spin filters, with their spin polarization controllable by atomic arrangement and bias voltage, as shown through density functional theory calculations.

Contribution

It introduces a detailed theoretical analysis of spin filtering in Fe-doped armchair graphene nanoribbons, highlighting the impact of atomic configuration on spin polarization control.

Findings

High spin polarization achieved with specific Fe atom arrangements.

Switching between majority and minority spin polarization is possible.

Bias dependence is crucial for accurate current-voltage characterization.

Abstract

The spin filter capability of a (0,8) armchair graphene nanoribbon with Fe atoms at substitutional sites is investigated by density functional theory in combination with the non-equilibrium Greens function technique. For specific arrangements, a high degree of spin polarization is achieved. These include a single substitution at an edge position or double substitution in the central sector of the transmission element. The possibility of switching between majority and minority spin polarization by changing the double substitution geometry is predicted. Including the bias dependence of the transmission function proves to be essential for correct representation of the spin-resolved current-voltage profiles.