Diffusion of Cu hexamer islands on Cu(111) and Ag(111) was studied using a molecular dynamics simulation technique with many-body potentials obtained from the embedded atom method. Simulations were carried out at temperatures 300, 500 and 700K, showing that shape-changing multiple-atom processes were more helpful for the diffusion rather than concerted motion of islands. Arrhenius plots of the diffusion coefficients provide effective energy barrier values of 161.29meV for Cu(111) and 179.34meV for Ag(111) surfaces. At 700K, one pop-up atom among island atoms was observed with correlative changes in the position and shape of the lower-layer adatoms.

Diffusion of Six-Atom Cu Islands on Cu(111) and Ag(111). S.S.Hayat, I.Ahmad, M.A.Choudhry: Chinese Physics Letters, 2011, 28[5], 053601