Dynamic study of a surface-confined alloy in an ultrathin Ag/Pt(111) film

During alloy formation of the surface-confined fcc(111) systems, we demonstrate that the energy barrier of diffusion for surface atoms can be determined from a dynamic study of a surface alloy by low-energy electron diffraction. The corresponding energy barrier of (Formula presented) was obtained from data consistent with the results of Monte Carlo simulations in submonolayer Ag/Pt(111) films. Ultrathin Ag film deposited at 360 K shows pseudomorphic growth. Annealing of a submonolayer ultrathin Ag film above 550 K causes formation of a two-dimensional surface alloy. After alloy formation, the vibration of surface atoms is enhanced and the enhancement could be as large as 70%.