Dresden 2006 – wissenschaftliches Programm

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SYET: Dynamics of electron transfer processes at surfaces

SYET 1: Dynamics of electron transfer processes at surfaces

SYET 1.4: Hauptvortrag

Donnerstag, 30. März 2006, 11:30–12:00, HSZ 04

Ab initio calculation of charge transfer at surfaces — •Daniel Sánchez-Portal — Unidad de Física de Materiales, Centro Mixto CSIC-UPV/EHU, and Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, 20018 Donostia - San Sebastián, Spain

In this contribution I will present a scheme for the calculation of the transfer rates of electrons from adsorbates to metallic substrates. The electrons initially reside in electronic excited states in the adsorbates. Our calculations are based on first-principles density-functional calculations of the combined adsorbate-substrate system using finite slabs. These results are then combined with bulk calculations of the substrate material to obtain the Green’s function of the semi-infinite system. Our results are thus based on a realistic description of the electronic structure of both systems, the substrate and the adsorbate, and the interaction between them. This scheme has also been applied recently to the calculation of the elastic width of quantum well states at alkali overlayers on Cu(111) [1]. We focus here in two cases: i) the c(4x2)-S/Ru(0001) surface [2], and ii) Ar monolayers on Ru(0001) [3]. In the first case we find a charge transfer time well below the femtosecond scale, in very good agreement with the experimental measurements based on core-hole-spectroscopy using Coster-Kronig decay channels. Also for the case of Ar on Ru our calculated values and trends are in good agreement with the experimental observations.

[1] C. Corriol, V. M. Silkin, D. Sánchez-Portal, A. Arnau, E. V. Chulkov, P.M. Echenique, T. von Hofe, J. Kliewer, J. Kröger, and R. Berndt, Role of elastic scattering in electron dynamics at ordered alkali overlayers on Cu(111), to appear in Phys. Rev. Lett.

[2] A. Föhlisch, P. Feulner, F. Hennies, A. Fink, D. Menzel, D, Sánchez-Portal, P. M. Echenique, and W. Wurth, Direct observation of electron dynamics in the attosecond domain, Nature (London) 436, 373 (2005)

[3] D. Sánchez-Portal, D. Menzel and P. M. Echenique, to be published