Surface vacancy diffusion on Cu(111): a computer simulation study

The diffusion of a surface vacancy on Cu(111) has been studied by means of molecular dynamics in conjunction with the many-body potential derived from the second-moment approximation of the tight-binding model. The calculatio ns performed in the high-temperature range reveal that the surface vacancy diffusion occurs mainly via the random nearest-neighbour hops with the acti vation energy close to the static migration barrier. Small contributions of the third-neighbour surface-layer jumps and jumps between the first and th e second layer are also recorded. The latter jumps are likely to be possibl e due to some dynamical co-operative effect among neighbouring atoms around a vacancy that effectively reduces the inter-layer migration barrier. (C) 1998 Elsevier Science B.V. All rights reserved.