Study of step fluctuations on Ag(100) electrodes in the presence of the electric field of the double layer

HARALD IBACH; KAY POETTING; PAOLA QUAINO; WOLFGANG SCHMICKLER

Bahia Blanca

Congreso; Tercer Encuentro de Fisica y Quimica de Superficies (FyQS-III); 2007

Recently, it was found that the stability and dynamics of nanostructures often depend exponentially on the electrode potential, an effect which can be ascribed to the interaction of local dipole moments with the electric field of the double layer [1].To verify this result and understand the mechanism involved, we study the step fluctuactions of silver islands on Ag(100) electrodes through the evaluation of the stiffness coefficients in the following temperature range: 300K-500K in the presence of the electric field of the double layer (3.1010 < Eef / V/m < 7.1010). The studies were performed using a combination of DFT calculations and Kinetic Monte Carlo simulations (KMC).The diffusion rates of the elementary processes were the basis for the Monte Carlo simulations, and they were calculated by a combination of embedded atom potentials and the dipole moments for the most important processes calculated by DFT.Preliminary results show that the strong interaction between the electric field and the surface dipole moments leads to an increase of the fluctuations of the system and, consequently, a decrease in the values of the stiffness coeffcients.[1] M. Giesen, G. Beltramo, S. Dieluweit, J. Müller, H. Ibach, W. Schmickler, Surf. Sci, 595 (2005) 127.