NEW APPROACH FOR DETERMINATION OF DIFFUSION PARAMETERS OF ADATOMS

A new approach for the determination of activation energy and attempt frequency for the diffusion of single adatoms on a surface is proposed and demonstrated for Pt adatom diffusion on Pt(lll). The method is ba sed on a combination of low temperature scanning tunneling microscopy (STM) measurements and kinetic Monte Carlo simulations. The method inv olves only a minimum of assumptions and is independent of classical nu cleation theory. This independence allows one to analyze the applicabi lity of the latter. In addition, it is found that the measurement of t he mean square displacement of individual adatoms is influenced by the STM tip.