GROWTH INVESTIGATIONS OF ULTRATHIN Ag FILMS ON Pt(111) USING STM AND DYNAMICAL WORK FUNCTION MEASUREMENTS

The growth of Ag on Pt(111) has been studied with in situ work function change measurements and STM at deposition temperatures of 350 K and 520 K. The strain of the compressively stressed Ag monolayer is relieved in the submonolayer regime by the development of two different reconstructions. One of these reconstructions occurs only at higher coverages (Θ<0.85 ML), partially displacing the other reconstruction which is found on all submonolayer Ag films. For coverages beyond one monolayer the first monolayer Ag becomes pseudomorphic with the Pt(111) substrate. Based on a different work function behavior for a deposition at 350 K and 520 K, respectively, we suggest different mechanisms for the disappearance of these reconstructions during the completion of the first Ag layer and the initial growth of the second layer.