Pop-up of atoms among copper 13-atom island on Ag(1 1 1)

Results of molecular dynamics simulation of the diffusion of two-dimensional 13-atom Cu island on Ag(1 1 1), using many-body potentials obtained from the embedded-atom method, are presented. Simulations carried out at three different temperatures – 300, 500 and 700 K – show shape-changing multiple-atom processes are responsible for the diffusion of islet. Arrhenius plot of the diffusion coefficients provide effective energy barrier of 232.06 ± 10 mev and diffusion prefactor 1.034 × 1013 Å2/s. A striking and interesting feature of pop-up of single-atom at 500 K and three-atom at 700 K among 13-atom island is observed, with correlative changes in position and shape of the lower-layer adatoms. Surface dynamics in the presence of an island produced dislocations and fissures near the island.