Metal-terminated Graphene Nanoribbons

TL;DR

This study uses first-principles calculations to explore how metal terminations affect the electronic and magnetic properties of zigzag graphene nanoribbons, revealing potential for spintronic applications.

Contribution

It provides a detailed analysis of how different metal terminations alter the magnetic and electronic states of ZGNRs, introducing new possibilities for device engineering.

Findings

TM terminations induce metallic behavior in AFM ZGNRs.

Noble metal terminations keep ZGNRs semiconducting.

Fe-ZGNR junctions show high magnetoresistance.

Abstract

We have investigated structure, electronic, and magnetic properties of metal-terminated zigzag graphene nanoribbons (M-ZGNRs) by first-principles calculations. Two families of metal terminations are studied: (1) 3d-transition metals (TMs) Fe, Co, and Ni and (2) noble metals (NMs) Cu, Ag, and Au. All systems have spin-polarized edge states with antiferromagnetic (AFM) ordering between two edges, except Co-ZGNRs and Ni-ZGNRs which exhibit negligibly small energy differences between AFM and ferromagnetic states with the given ribbon width. In the AFM state the TM terminations transform semiconducting ZGNRs into metallic ones while the band gap remains in ZGNR with NM terminations. Ferromagnetic states of M-ZGNRs with TM terminations show a high degree of spin polarization at the Fermi energy. We predict a large magnetoresistance in Fe-ZGNR junctions with a low, uniform magnetic switching field.