Energetics of Pb heterostructures formation on the Cu (111) in the early stage of the deposition process

The structural and self-assembling characteristic of Pb heterostructures on the Cu (111) substrate in the early stage of the deposition process were investigated using a molecular dynamics simulation and density functional theory. The Pb islands formed on the Cu (111) surface were observed to diffuse actively in lateral directions following the layer-by-layer growth mode. A heptameric hexagonal island was found to be most stable under highly nonequilibrium conditions. This result can be explained by the tendency of Pb heterostructures, which have minimum surface energy, to have the maximum number of Pb-Pb bondings. In addition, the atomic binding energy, the surface diffusion coefficient prefactor, and the surface diffusion energy barrier for Pb adatoms were quantitatively calculated according to various shapes of Pb islands to determine the stability of the corresponding island.