表面Cu原子间相互作用对Cu(001)表面跳跃扩散行为的影响

采用嵌入原子方法的原子间相互作用势，利用准静态分子动力学模拟研究了Cu原子在Cu(001)表面吸附所导致的基体晶格畸变以及对其附近的另一个吸附原子自扩散行为的影响.研究结果表明，吸附原子的存在可以导致多达10层的Cu基体晶格产生畸变.两个吸附原子所产生的晶格畸变应力场之间的相互作用，可以导致吸附原子运动活性的增加.通过比较同一路径上往返跳跃扩散势垒的差异发现，在原子间相互作用势的有效距离之外，两个吸附原子的扩散行为可以认为是存在晶格畸变应力场相互作用的两个独立吸附原子的扩散；在原子间相互作用势的有效距离之 关键词： 表面吸附原子 晶格畸变 表面二聚体 扩散

Influence of interaction between Cu adatoms on the hopping diffusion on Cu(001) surface

Based on the atomic interaction potential with the embedded atom, molecular dynamics simulation was used to study the variation of Cu(001) surface caused by a Cu adatom and the hopping barriers of another Cu adatom in its vicinity. The results show that the Cu adatom may distort the positions of Cu atoms in the substrate to the extent of 2 lattice constants and the influence is as deep as 10 layers. Due to the interaction of the stress field between two adatoms, the hopping diffusion barriers of the adatoms are decreased and the adatoms are more active in diffusion than a single adatom. By comparing the difference of hopping barriers to and fro along the same diffusion path, the migrating behavior of the adatoms can be divided into two kinds of diffusion, depending on the distance between the two adatoms. If they are at a distance longer than the effective distance of the atomic interaction potentials, the diffusion of adatoms is affected only by the interaction of the stress field between two adatoms. If they are at a distance shorter than the effective distance of the atomic interaction potentials, the two adatoms should be considered as an ad-dimer in different states.