Models for adatom diffusion on fcc (001) metal surfaces

We present a class of models that describe self-diffusion on fee (001) meta l substrates within a common framework. The models are tested far Cu(001), Ag(001), Au(001),Ni(001), and Pd(001), and found to apply well for all of t hem. For each of these metals the models can be used to estimate the activa tion energy of any diffusion process using a few basic parameters that may be obtained from experiments, ab initio or semiempirical calculations. To d emonstrate the approach, the parameters of the models are optimized to desc ribe self-diffusion on the (001) surface, by comparing the energy barriers to a full set of barriers obtained from semiempirical potentials via the em bedded atom method (EAM). It is found that these models with at most four p arameters, provide a good description of the full landscape of hopping ener gy barriers on fee (001) surfaces. The main features of the diffusion proce sses revealed by EAM calculations are quantitatively reproducible by the mo dels. [S0163-1829(99)01227-8].