Regensburg 2007 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 17: Poster Session I (Nanostructures at Surfaces; Metal Substrates: Epitaxy and Growth; Methods: Scanning Probe Techniques; Phase Transitions)

O 17.3: Poster

Montag, 26. März 2007, 17:30–20:30, Poster C

Structural and electronic properties of SiC and BN nanotubes — •Björn Baumeier, Peter Krüger, and Johannes Pollmann — Institut für Festkörpertheorie, Universität Münster, Wilhelm-Klemm-Str. 10, 48149 Münster

The initial discovery of carbon nanotubes (NTs) in 1991 has sparked considerable interest in this kind of nanosized one-dimensional structures due to their unique physical properties and the associated potential for applications.

We present the results of a comparative ab initio study of composite single-walled SiC and BN nanotubes in zigzag and armchair configurations. Using pseudopotentials that incorporate self-interaction-corrections in density functional theory calculations, we arrive at reliable quantitative results for both structural and electronic properties of the respective bulk crystals, as compared to available experimental data. Within this approach, we investigate the dependence of the strain energy, Young modulus, atomic relaxation and electronic structure on NT diameter. Qualitatively, both wide-band-gap materials show similar behavior with respect to the formation of a radially buckled geometry upon atomic relaxation or the saturation of the Young modulus and band-gap energies for large NT diameters. The calculated fundamental gap of zigzag NTs varies more strongly for small and medium tube diameters than that of their armchair counterparts, which is due to a more pronounced curvature-induced rehybridization effect on conduction band states.