Long jumps contribution to the adatom diffusion process near the step edge: The case of Ag/Cu(110)

Abstract

In this work, the diffusion of a single Ag adatom on a low-index Cu surface (110) in the presence of a step edge is studied using the embedded-atom method (EAM). Molecular static simulation is carried out in order to calculate the activation energy of different diffusion processes. Our findings are in a good agreement with results existing in the literature indicating that adatom diffusion via jump process is more favored than the other mechanisms. The activation energy corresponding to diffusing via hopping is found to be 0.25 eV (at 0 K). On the other hand, the activation barrier calculated by molecular dynamics (MD) simulation for a large range of temperature (310–500 K) is found to be around 0.25 eV for both upper and lower position leading to a good agreement between static and dynamic calculations. The prefactor for Ag adatom self-diffusion via hopping on Cu(110) surface near the step edge is examined. The results show that the prefactors are 2.7 and 3.6 × 104 cm2 s−1 for the upper and lower position, respectively. This is in line with the value of 10−3 cm2 s−1 that is generally adopted. We also found that long jumps occur frequently in this system and their contribution cannot be neglected.