Molecular dynamics and kinetic Monte Carlo simulations of Fe island growth on Cu(111)

Abstract

We have performed extensive molecular dynamics (MD) simulations of a 0.07 ML coverage of Fe adatoms on Cu(111) at 300 K using a many-body interaction potential from the molecular dynamics/Monte-Carlo corrected effective medium theory. The Fe atoms were deposited randomly and then followed for two hundred picoseconds (ps) while annealing at a temperature of 300 K. The results of these MD simulations were analyzed to understand the general features of island growth. One finding was that islands as large as four atoms are only one of magnitude less mobile than monomers. Thus, the mobility of small islands played a significant role in the growth of large islands. In addition, the presence of next-nearest neighbor attractions was found to increase the speed of this growth. Another finding was that the Fe islands obtained their equilibrium structures only very slowly compared to the times of aggregation or coalescence. The MD results were used to construct and test several kinetic Monte Carlo models that incorporated the newly identified processes. Considering these MC models, we discuss some details of island structure, stability and aggregation.