Diffusion mechanisms for iron on tungsten |
| |
Authors: | D Spišák J Hafner |
| |
Institution: | Institut für Materialphysik and Center for Computational Materials Science, Universität Wien, Sensengasse 8/12, A-1090 Wien, Austria |
| |
Abstract: | Diffusion of iron atoms on clean W(1 0 0) and W(1 1 0) as well as on Fe/W(1 0 0) and Fe/W(1 1 0) surfaces was investigated by means of exhaustive first-principle calculations. Comparison of the activation energy barriers obtained for hopping and exchange migration processes shows that the surface diffusion proceeds via jumps to the nearest sites. The activation energies are higher for Fe adatom on clean tungsten than those for Fe adatoms moving on iron-covered tungsten. The magnetism of the underlying Fe/W(1 0 0) films has a pronounced influence on the diffusion, as evidenced not only by a reduced activation energy barrier but also by a change of the stable adsorption place. Fe atoms reaching step edges are trapped there and eventually diffuse along the steps more slowly than the adatoms on the terraces. The rate of diffusion increases upon depositing a row of Fe atoms along steps. |
| |
Keywords: | Adatoms Density functional calculations Iron Surface diffusion Tungsten |
本文献已被 ScienceDirect 等数据库收录! |