Dresden 2011 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 12: Metal substrates: Adsorption of O / H and inorganic molecules I
O 12.8: Vortrag
Montag, 14. März 2011, 16:45–17:00, WIL A317
First-Principles Diffusion Barrier of O at Pd (100): A Benchmark beyond LDA/GGA — •Wei-Bing Zhang1,2, Yongsheng Zhang1, Jörg Meyer1,2, and Karsten Reuter1,2 — 1Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin — 2Technische Universität München
The diffusion of adsorbates at a solid surface is a core elementary process of critical relevance for many functionalities. The accurate determination of diffusion barriers is correspondingly an important aspect in first-principles kinetic modeling. At extended metal surfaces the state-of-the-art for this is still local (LDA) and semi-local (GGA) density-functional theory. Critically scrutinizing the reliability of such description for the diffusion of O atoms at Pd(100) we first use a cluster expansion approach to separate the overall diffusion barrier into the isolated-adatom limit and contributions arising from lateral interactions with other O adsorbates. Comparing LDA and GGA data suggests that the latter component is surprisingly well described already at this level of theory. However, comparison against experiment reveals a significant error for the barrier in the isolated O adatom limit. We therefore use an exchange-correlation correction approach based on finite cluster calculations [1] to assess the performance of higher level theory, including hybrid and RPA functionals. [1] Q.M. Hu, K. Reuter, and M. Scheffler, Phys. Rev. Lett. 98, 176103 (2007).