Theoretical study of the dynamics of gold islands on Au(100)

KAY POETTING; PAOLA QUAINO; WOLFGANG SCHMICKLER; TIMO JACOB

Alemania

Congreso; Verhandlungen der Deutschen Physikalischen Gesellschaft 71 Annual Meeting 2007 and DPG Spring meeting of the Division Condensed Matter; 2007

Deutschen Physikalischen Gesellschaft

Nanostructures on metal electrodes are presently the subject of intensiveinvestigations because they are expected to play an importantrole in future nanotechnologies. Their stability and dynamics has beenfound to depend exponentially on the electrode potential, an effectwhich we ascribe to the interaction of local dipole moments with theelectric field of the double layer. In order to verify the validity of thisconjecture, and to clarify the details of the underlying mechanism, wehave investigated the dynamics of gold island on Au(100), which hasbeen the subject of intense experimental investigations, by a combinationof DFT calculations and kinetic Monte Carlo simulations. Forthis purpose, we have calculated the diffusion barriers and associateddipole moments for several important elementary processes by DFT.These results were combined with embedded atom potentials in orderto generate the rates for all possible steps, which were then used as thebasis for kinetic Monte Carlo simulations. In this way we have investigatedboth the dynamics of single islands and the Ostwald ripeningof two islands of different sizes. Preliminary results indicate a strongeffect of the field on energetic parameters like the step line tensionand the kink energy, and on the rate of particle exchange and Ostwaldripening.