Using embedded-atom-method potential, adatom and a vacancy diffusion processes were simulated in detail for three Fe surfaces, (110), (100) and (111). The results revealed that adatom adsorption energies and diffusion migration energies on these surfaces exhibited a similar monotonic trend to that of the relative layer spacing relaxation, R(110) < R(100) < R(111), adsorption energy, Ea(110) < Ea(100) < Ea(111), diffusion migration energy, Em(110) < Em(100) < Em(111). However, for a vacancy, formation and migration energies exhibited a different trend, formation energy, Ef(111) < Ef(100) < Ef(110), migration energy, Em(111) < Em(110) < Em(100). On the Fe (110) surface, simple jumping of an adatom (or a vacancy) was the main diffusion mechanism with relatively low migration energy barrier. Nevertheless, exchange with a surface atom played a dominant role in surface diffusion on the Fe(100) and Fe(111) surfaces.

A Molecular Dynamics Simulation of Self-Diffusion on Fe Surfaces. Wang, C., Qin, Z., Zhang, Y., Sun, Q., Jia, Y.: Applied Surface Science, 2012, 258[10], 4294-300