A molecular dynamics simulation of self-diffusion on Fe surfaces

Using embedded-atom-method (EAM) potential, an adatom and a vacancy diffusion processes have been simulated in detail by molecular dynamics on three Fe surfaces, Fe (1 1 0), Fe (1 0 0), and Fe (1 1 1). Our results reveal that adatom adsorption energies and diffusion migration energies on these surfaces have similar monotonic trend to the relative layer spacing relaxation, R(110) < R(100) < R(111), adsorption energy, image, diffusion migration energy, image. However, for a vacancy, formation and migration energies have a different trend, formation energy, image, migration energy, image. On the Fe (1 1 0) surface, simple jumping of an adatom (or a vacancy) is the main diffusion mechanism with relatively low migration energy barrier; nevertheless, exchange with a surface atom plays a dominant role in surface diffusion on the Fe (1 0 0) and Fe (1 1 1) surfaces.