Dresden 2011 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 36: Poster Session II (Metals; Nanostructures at surfaces; Surface or interface magnetism; Spin-Orbit Interaction at Surfaces; Electron and spin dynamics; Surface dynamics; Methods; Theory and computation of electronic structure)

O 36.41: Poster

Dienstag, 15. März 2011, 18:30–22:00, P4

Structures of metal electrodes at the solid-liquid interface studied by density functional theory — •Xiaohang Lin and Axel Groß — Institute of Theoretical Chemistry, Ulm University, D-89069 Ulm, Germany

Recently, the operation of an electrochemical atomic-scale quantum conductance switch has been demonstrated, which is controlled by an external electrochemical voltage applied to an independent third gate electrode [1]. However, the microscopic processes underlying this atomic switch are still unclear. Using density functional theory (DFT) calculations, we have addressed the structure of Ag and Pb metal surfaces which are both used as electrode materials for the switch. We have considered the presence of water layers and the self-diffusion on flat and stepped metal surfaces in order to contribute to the understanding of electrodeposition. We find that the substantial difference in the lattice constants between Ag and Pb leads to significant changes, as far as the stable water structure at the metal-water interface is concerned. With respect to the metal diffusion, the DFT results indicate that exchange processes can have considerably lower barriers than hopping processes.

[1] F.-Q. Xie et al., Phys. Rev. Lett. 93, 128303 (2004).