EFFECT OF ADSORPTION ON SURFACE ROUGHENING

Employing the restricted-solid-on-solid model, we show that adsorption may result in a decrease of the roughening temperature T-R due to (i) indirect next-nearest-neighbor adsorbate-substrate repulsion, (ii) at tractive nearest-neighbor adsorbate-substrate lateral interaction, or (iii) repulsive adsorbate-adsorbate lateral interaction. In all these cases, the ratio of T-R near saturation and for a clean surface is giv en by a simple combination of the corresponding interactions. The cove rage dependence of T-R, obtained for case (i) by Monte Carlo simulatio ns, deviates from the mean-field-type prediction. Adsorbate-induced su rface roughening observed in catalytic reactions is also briefly discu ssed. [S0163-1829(97)50540-6].