An improved theory for temperature-dependent Arrhenius parameters in mesoscale surface diffusion

作者：Dalton A S; Seebauer E G^*

来源：Surface Science, 2007, 601(3): 728-734.

DOI：10.1016/j.susc.2006.10.041

• diffusion
• interface formation
• composition, segregation
• defects and impurities
• diffusion of adsorbates, kinetics of coarsening and aggregation

Experiments on metals typically show an abrupt change in the Arrhenius behavior of surface self-diffusion at temperatures near 60-75% of the bulk melting point. To explain this phenomenon, we propose based on correlational evidence that the most common mechanism for surface self-diffusion is one in which adatoms dominate low-temperature transport, while surface vacancies dominate at high temperatures. The high-temperature dominance of vacancies results from their substantially higher entropy of diffusion, which is a consequence of the large vibrational displacements of surface atoms relative to the bulk. This phenomenon may also explain the Arrhenius behavior on some non-metal surfaces.

• 出版日期2007-2-1