Electronic and magnetic properties of zigzag graphene nanoribbons on the (111) surface of Cu, Ag and Au

TL;DR

This study uses ab initio calculations to explore the structural, electronic, and magnetic properties of zigzag graphene nanoribbons on Cu(111), Ag(111), and Au(111) surfaces, revealing edge states but limited magnetization except in specific cases.

Contribution

It provides new insights into how substrate interactions and hydrogen termination influence the magnetic properties of graphene nanoribbons on noble metal surfaces.

Findings

Edge states are present on all nanoribbons on these surfaces.

Significant edge magnetization occurs only in H-terminated nanoribbons on Au(111).

H-free nanoribbons show peaks in local density of states without indicating magnetism.

Abstract

We have carried out an ab initio study of the structural, electronic and magnetic properties of zigzag graphene nanoribbons on Cu(111), Ag(111) and Au(111). Both, H-free and H-terminated nanoribbons are considered revealing that the nanoribbons invariably possess edge states when deposited on these surfaces. In spite of this, they do not exhibit a significant magnetization at the edge, with the exception of H-terminated nanoribbons on Au(111), whose zero-temperature magnetic properties are comparable to those of free-standing nanoribbons. These results are explained by the different hybridization between the graphene 2p orbitals and those of the substrates and, for some models, by the sizable charge transfer between the surface and the nanoribbon. Interestingly, H-free nanoribbons on Au(111) and Ag(111) exhibit two main peaks in the local density of states around the Fermi energy, which originate from different states and, thus, do not indicate edge magnetism.