Roughening transition in the presence of adsorbates

The influence of adsorbates on the roughening of solid substrates is discussed in terms of the solid-on-solid model coupled to a generalized lattice gas model. It is shown that the adsorbate may increase or decrease the roughening temperature Tᵣ, depending on the specificity of the height-dependent lateral interaction and adsorbing potential. The decrease of Tᵣ is nonmonotonic with increasing coverage. The substrate corrugation is shown to enhance or depress the adsorption, depending on the preferred height difference at neighboring sites.