First-principle investigation of the formation of Cs-dimer-chains upon adsorption on InAs(110)

We have performed first-principle calculations to investigate the formation of Cs chains on an InAs(110) surface at submonolayer coverage. By studying the energetics of different possible configurations in which Cs atoms adsorb on and between surface ions, we have identified the most stable geometry. The stable geometry is characterized by the presence of asymmetric dimer chains, in agreement with recent scanning tunneling microscopy images. We find an important effect of substrate-mediated Cs-Cs correlation. Adsorption occurs simultaneously at two different surface sites. The binding of Cs atoms to surface atoms essentially involves cations, while there is no direct adsorbate-anion interaction.