Regensburg 2013 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 56: Oxide Surfaces I

O 56.6: Vortrag

Mittwoch, 13. März 2013, 17:15–17:30, H45

A first-principles view of the Cabrera-Mott Model of Metal Oxidation — •Anders Hellman, Jakub Baran, and Henrik Grönbeck — Chalmers, Applied Physics, Göteborg, Sweden

Oxidation of metals is an every-day phenomenon, which can be an unwanted process, e.g., automotive corrosion. However, under controlled conditions oxidation is of enormous practical importance, both in industry and science. The work of Cabrera and Mott (CM) in the mid-twenty century still remains the main theoretical model for growth of thin oxides on metals [1]. Recently, Zhou et al. [2] have experimentally shown that the limiting thickness of the aluminum oxide on Al(111) can be tuned by the oxygen pressure. Our first-principles calculations [3] support many of the key assumptions of the CM model. For instance, based on our results we estimated the limiting thickness of Al2O3 on Al(111) to around 16 Å, which agrees well with the experimental data. Furthermore, the charge transfer to adsorbed oxygen molecules generates a Mott potential which value also agrees well with experimental estimates. However, the underlying reason for observing a limiting thickness of the protective oxide is not the diminishing effect of the Mott potential. Instead we will provide another underlying reason for the limiting thickness based on our first-principles calculations.

References 1.*Cabrera, N. and N.F. Mott, Reports on Progress in Physics 12 163 (1948). 2.*Cai, N., et al., Phys. Rev. Lett. 107 035502 (2011). 3.*Baran, J., Grönbeck, H., Hellman, A., submitted