Numerical determination of the structure of registered rare gas monolayers adsorbed on dielectric or metallic substrates

Abstract

A perturbative determination of the distortion of an atomic monolayer adsorbed on corrugated dielectric or metallic substrates is developed. Among the seven variables required to characterize the planar monolayer, four describe the position and orientation of the monolayer as a whole, with respect to an absolute substrate direction, and three describe the distortion of the monolayer primitive cell. Along the direction perpendicular to the surface, the monolayer atoms are more or less moved with respect to the planar configuration, according to the nature of the substrate sites. The computed values of these perpendicular distortions, which are consistent with the requirement to minimum interaction energy between the adsorbate and the substrate, are then used to determine the primitive supercell of the registered (or partially registered) monolayer and the most stable geometry of the monolayer. A numerical application of this method is done to interpret the frustration phenomenon observed for the argon monolayer adsorbed on a square MgO(100) substrate.