Indirect adsorbate-adsorbate interactions mediated through the surface electronic structure of the Si(100) surface

摘要

Indirect adsorbate-adsorbate interactions between adsorbed ammonia (NH_3) molecules on the Si(100) surface are investigated using density functional theory.Two different nonlocal effects mediated through the surface electronic structure are observed: "poisoning" and hydrogen bonding.We find that adsorbed NH_3 "poisons" adsorption of NH_3 on neighboring Si dimers on the same side of the dimer row whereas neighboring NH_2(a) groups favor this configuration.Adsorption of NH_3 involves charge transfer to the surface that localizes on neighboring Si dimer atoms,preventing adsorption of NH_3 at these sites.These indirect interactions are similar to Friedel-type interactions observed on metal surfaces with an estimated range of less than 7.8 A on the Si(100) surface.These interactions may be manipulated to construct local ordering of the adsorbates on the surface.