EFFECT OF STRAIN ON THIN-FILM GROWTH - DEPOSITION OF NI ON AG(100)

The results of Monte Carlo simulations of the structure and energetics of Ni thin films grown on Ag(100) are discussed. Despite a 13.9% lattice mismatch, layer-by-layer growth of pseudomorphic Ni is favored over an incommensurate Ni(111) structure, up to approximately approximately 3.2 ML Ni. Reconstruction or clustering of the Ni overlayer is seen at submonolayer to monolayer coverages. The pseudomorphic multilayer film has a tetragonal structure due to the expansive intralayer strain inducing a compressive interlayer stress. The tetragonal Ni(100) overlayer appears metastable, since allowing interdiffusion via exchange of Ni and Ag atoms leads to a thermodynamically favored Ag/Ni/Ag(100) sandwich structure. A buckled, close-packed Ni(111) thin film structure is preferred at higher coverages and is found to inhibit interdiffusion of Ag atoms. A direct commensurate-incommensurate phase transition is never observed.