Dresden 2017 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 60: Solid-Liquid Interfaces: Structure, Spectroscopy, Reactions and Electrochemistry

O 60.9: Poster

Dienstag, 21. März 2017, 18:30–20:30, P2-OG2

DFT-study of adsorption and diffusion including electric field effect for halogen atoms on the (001) surfaces of Cu, Ag, Au and an AgAu-alloy — •Alexandra Davila, Jan Thiel, Nico Reimann, and Eckhard Pehlke — Institut für Theoretische Physik und Astrophysik, CAU Kiel, Germany

The growth dynamics in metal electrodeposition experiments depend on the electric potential of the sample electrode [1]. This has been ascribed to the dependence of the activation energy for surface diffusion of the metal adatoms on the sample potential. The composition of the electrolyte, especially halides, e.g. Cl⁻ ions, will also play an important role on the surface mobility [1]. Motivated by these results, we present a DFT based analysis [2,3] of activation energies under homogeneous electric field, which simulates the effect of the sample potential, for halogen (Cl, Br, I) adatoms on the (001) surfaces of Cu, Ag, and Au. The effect of electric field on the energy differences between hollow and brigde sites follow the linear relation derived by Giesen et al. [4], with deviations from linearity less than 10 meV for electric field ranging from -0.6 V/Å to 0.6 V/Å. In case of I/Au(001) we observe a qualitative change of the PES as a function of electric field. Furthermore, we show changes of the topology of the PES for the case of an adsorbed Cl-atom on an AgAu alloy.

[1]T. Tansel and O. Magnussen, Phys. Rev. Lett. 96 (2006).

[2]//www.vasp.at.

[3]P. Giannozzi et al., J. Phys. Condens. Matter 21, 395502 (2009).

[4] M. Giesen et al., Surf. Sci. 595, 127 (2005).