The adsorption of In atoms on the clean Si(001) surface as a function of In coverage is studied using density functional theory. It is shown that the reactivity of Si(001) is locally enhanced by In adsorption and leads to the formation of one-dimensional In chains. It is demonstrated that the formation of such chains can be described as a two-stage process. In the initial stages of chain formation (≤3 In atoms), the binding energy of each additional In atom is strongly dependent on the number of In adatoms, and where they are adsorbed on the surface. The most stable configuration for a single In atom is found to be an end-dimer-bridge monomer structure, while that for two In atoms is the parallel inter-dimer-row (ad-dimer) configuration. In the second stage of chain growth (>3 In atoms), the binding energy values of the additional In atoms adsorbed on Si(001) are essentially constant. All of the In structures formed in stages one and two which contain In monomers are determined to be metallic, while those consisting of only In-In dimers are semiconducting.
Physical Review B : Condensed Matter and Materials Physics Vol. 81, Issue 8, p. 085424-1-085424-10