Regensburg 2013 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 21: Graphene - Electronic Properties and Transport 1 (jointly with DS, HL, MA, and O)

TT 21.7: Vortrag

Montag, 11. März 2013, 17:30–17:45, H17

Electronic and magnetic properties of zigzag graphene nanoribbons on the (111) surface of Cu, Ag and Au — •Yan Li¹, Wei Zhang¹, Markus Morgenstern², and Riccardo Mazzarello¹ — ¹Institute for Theoretical Solid State Physics and JARA, RWTH Aachen University, D-52074 Aachen, Germany — ²II. Physikalisches Institut B and JARA-FIT, RWTH Aachen University, D-52074 Aachen, Germany

We have carried out an ab initio study of the structural, electronic and magnetic properties of zigzag graphene nanoribbons (GNRs) on Cu(111), Ag(111) and Au(111). Both H-free and H-terminated GNRs are considered revealing that the nanoribbons invariably possess edge states when deposited on these surfaces. In spite of this, they do not exhibit magnetism at the edge, with the exception of H-terminated GNRs on Au(111), whose zero-temperature magnetic properties are comparable to those of free-standing GNRs. The absence of edge magnetism is due to the hybridization between the 2pz orbitals of the carbon atoms and the d states of the metal and, for some models, to the charge transfer between the GNR and the surface, which shifts the edge state away from the Fermi level. Only in the case of H-terminated GNRs on Au(111) is the interaction between the substrate and the GNR sufficiently weak so as not to affect the magnetic properties of the edge state significantly.