Giant Surface Stress in Heteroepitaxial Films: Invalidation of a Classical Rule in Epitaxy

The first few monolayers of silver deposited on the Pt(111) surface bear a giant compressive surface stress. The stress is more than an order of magnitude larger than the stress caused by the lattice mismatch and results presumably from the charge transfer from Ag to Pt. Upon annealing to 600 K, the stress relaxes by the formation of a mixed Ag-Pt interface. The result shows that the consideration of surface energies and lattice mismatch is not sufficient for the prediction of the growth mode.