Fractal growth of LiF on Ag(111) studied by low-temperature STM

We studied the fractal growth of LiF on Ag(lll) at 77 K using low-temperature scanning tunneling microscopy. The observed island density as a function of the flux and the island density distribution reveal consistency with nucleation theory for the critical cluster size corresponding to i=1. The migration barrier for LIF monomers was estimated to be of the order of several tens of meV. The ramified (100)-oriented LiF aggregates exhibit a fractal dimension of d=1.75+/-0.01. No shape transition to dendritic growth was observed for fluxes ranging from F=2.4 x 10(-2) to F=2.0 x 10(-5) ML s(-1) which is attributed to the different symmetries of adsorbate and substrate. (C) 2000 Elsevier Science B.V. All rights reserved.