The conductance of monoatomic As and Ag chains deposited onto silicon steps evaluated using a simplified scattering approach

The purpose of this study is the assessment of the conductance of deposited atomic chains. The structures considered are linear chains of covalent and metallic atoms, i.e. As and Ag, deposited onto monolayer steps of the Si( 100) surface. The study is based on the extended Debey-Huckel theory, used for the evaluation of the electronic structure and conductance, and the calculations analyse the relationship between the structural parameters of steps, their binding and adsorption energies and the conductance. This evaluation shows that the binding strength of the deposited chains is perceptibly enhanced above that of the free-standing chains and the cohesion of the steps is not lowered by the deposited structures. While the length of the chain has no effect on the total electronic structure, its composition and the adsorption sites are important and a functional relationship between these quantities and the adsorption energy is clearly observed. The central result of the calculations is that the conductance of the entire step and of the deposited chain have a dependence on these structural parameters similar to those of the binding and adsorption energies and their behaviour is parallel to that of the characteristic energies.