Berlin 2008 – scientific programme
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O: Fachverband Oberflächenphysik
O 18: Poster Session I - MA 141/144 (Atomic Wires; Size-Selected Clusters; Nanostructures; Metal Substrates: Clean Surfaces+Adsorption of Organic / Bio Molecules+Solid-Liquid Interfaces+Adsorption of O and/or H; Surface or Interface Magnetism; Oxides and Insulators: Clean Surfaces)
O 18.43: Poster
Monday, February 25, 2008, 18:30–19:30, Poster F
Co multilayers on diamond surfaces: Results from ab-initio studies — •Bernd Stärk, Peter Krüger, and Johannes Pollmann — Institut für Festkörpertheorie, Universität Münster
In recent years there has been an ever increasing interest in the development and understanding of metal-semiconductor hybrid systems. They may feature novel functionalities which are not feasible with metals or semiconductors alone combining, e.g., the high conductivity and spin-polarization of ferromagnets with the controllability of semiconductors.
In our work structural, electronic and magnetic properties of Co multilayers on diamond surfaces are investigated within the framework of density functional theory employing the local-spin-density approximation together with Gaussian orbital basis sets and norm-conserving pseudopotentials.
For one Co monolayer on a C(111)-(1×1) surface we find that Co adsorption in on-top positions is energetically most favorable. The attached Co monolayer has a weak magnetic moment of 0.69 µB, much smaller than that of an isolated Co(0001) monolayer, which we find to be 1.88 µB. This behavior can be attributed to the strong covalent bond forming between Co and C atoms. Adsorption of further Co(0001) layers results in a monotonous increase in the magnetic moment Mtop of the topmost Co layer. In the case of four Co adlayers Mtop is already close to the magnetic moment at the clean Co(0001) surface. The evolution of the magnetic moment with increasing number of Co adlayers will be discussed on the basis of the respective electronic structure.