Energetics and self-diffusion behavior of Zr atomic clusters on a Zr(0 0 0 1) surface

Abstract

Using a molecular dynamics method and a modified analytic embedded atom potential, the energetic and the self-diffusion dynamics of Zr atomic clusters up to eight atoms on α-Zr(0001) surface have been studied. The simulation temperature ranges from 300 to 1100K and the simulation time varies from 20 to 40ns. It’s found that the heptamer and trimer are more stable comparing to other neighboring non-compact clusters. The diffusion coefficients of clusters are derived from the mean square displacement of cluster’s mass-center and the present diffusion coefficients for clusters exhibit an Arrhenius behavior. The Arrhenius relation of the single adatom can be divided into two parts in different temperature range because of their different diffusion mechanisms. The migration energies of clusters increase with increasing the number of atoms in cluster. The differences of the prefactors also come from the diverse diffusion mechanisms. On the facet of 60nm, the heptamer can be the nuclei in the crystal growth below 370K.