A molecular dynamics simulation of self-diffusion on Fe surfaces

Abstract 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) E a ( 110 ) a E a ( 100 ) a E a ( 111 ) a , diffusion migration energy, E a ( 110 ) m E a ( 100 ) m E a ( 111 ) m . However, for a vacancy, formation and migration energies have a different trend, formation energy, E v ( 111 ) f E v ( 100 ) f E v ( 110 ) f , migration energy, E v ( 111 ) m E v ( 110 ) m E v ( 100 ) m . 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.