Terrace-dependent nucleation of small Ag clusters on a five-fold icosahedral quasicrystal surface

Nucleation of Ag islands on the five-fold surface of icosahedral Al–Pd–Mn is influenced strongly by trap sites. Submonolayers of Ag prepared by deposition at 365 K and with a flux of 1 × 10−3 monolayers/s exhibit a variation in Ag island densities across different terraces. Comparisons with previous work and with rate equation analysis indicate that trap sites are not saturated under these experimental conditions and that the difference in island densities is not necessarily due to variation in trap densities. While it could have a number of different origins, our results point to a terrace-dependent value of the effective diffusion barrier for Ag adatoms.