Effect of the attachment of ferromagnetic contacts on the conductivity and giant magnetoresistance of graphene nanoribbons

TL;DR

This study investigates how ferromagnetic contacts influence the electrical conductivity and giant magnetoresistance in graphene nanoribbons, revealing that contact geometry affects these properties differently.

Contribution

It provides a theoretical analysis of contact geometry effects on conductivity and magnetoresistance in GNRs using a tight-binding model and Green's functions.

Findings

End-contacted geometry enhances electrical conductivity.

Side-contacted geometry shows stronger spin-splitting effects.

Contact geometry impacts magnetoresistance behavior.

Abstract

Carbon-based nanostructures and graphene, in particular, evoke a lot of interest as new promising materials for nanoelectronics and spintronics. One of the most important issue in this context is the impact of external electrodes on electronic properties of graphene nanoribbons (GNR). The present theoretical method is based on the tight-binding model and a modified recursive procedure for Green's functions. The results show that within the ballistic transport regime, the so called end-contacted geometry (of minimal GNR/electrode interface area), is usually more advantageous for practical applications than its side-contacted counterpart (with a larger coverage area), as far as the electrical conductivity is concerned. As regards the giant magnetoresistance coefficient, however, the situation is exactly opposite, since spin- splitting effects are more pronounced in the lower conductive side-contacted setups.