Self-assembly of a two-dimensional molecular layer in a nonhomogeneous electric field: Kinetic Monte Carlo simulations.

Behavior of mobile adsorbed species can be affected by the presence of a strong non-homogeneous electric field. Such a field exists in the proximity of a biased tip of the scanning tunneling microscope. Depending on the electronic properties of the adsorbate and the polarity of the electric field, self-assembly of ordered structures on the surface can be facilitated or prevented. We use a kinetic Monte Carlo model to investigate the effect of the electric field on the assembly of planar molecules on weakly interacting surfaces. Using phthalocyanine molecules as a model system, we study mechanisms behind the results of our previous experimental study of electric-field controlled switching of molecular arrays. The complex interplay between intermolecular and field-molecule interactions is illustrated by detailed phase diagrams at various surface coverages.