Theoretical Study of Adatom Self-Diffusion on Metallic fcc 001 Surfaces

Based on the discrete variational method with the local-density-functional approximation (DVLDA), we propose molecular cluster models to simulate the physical surface with and without an adsorbed atom respectively. Our DV-LDA calculations favor the atomic exchange process along the 100 direction for AI self-diffusion on AI fcc (001) surfaces and the atomic bridge hopping process along the 110 direction for Cu self-diffusion on Cu fcc (001) surfaces. Based on all available experimental and theoretical results, there is an interesting parameter which can correlate the favored self-diffusion mechanism on metallic fcc 001 surfaces.