A kinetically driven growth mechanism: AlF3 over Cu(001)

Abstract

A new diffusion model based on kinematic properties and supported by Metropolis Monte Carlo free energy minimization and density functional theory calculations is proposed in this work. This new mechanism breaks the isotropic features of random adatom diffusion over a single crystal surface, not only about the main directions but also about the sense of movement. The present model allows us to understand all the anomalous growing features characterizing the behaviour of an insulator film, such as aluminum fluoride, over a metallic Cu(1 0 0) single crystal surface. The growth process of this system is characterized by several non-fully understood features, including a large diffusion coefficient, sticking at both sides of steps, and island atomistic arrangement along special directions. Although we focus our analysis on the AlF3/Cu(1 0 0) system, our conclusions may be extended to the diffusion of other complex molecules over different surfaces.