替位杂质对低能Pt原子与Pt(111)表面相互作用影响的分子动力学模拟

Numerical simulation of the influence of substitutional impurity on the interaction between low-energy Pt atoms and Pt(111) surface

采用嵌入原子方法的原子间相互作用势,通过分子动力学方法模拟了低能Pt原子与Cu,Ag,Au,Ni,Pd替位掺杂Pt(111)表面的相互作用过程,系统研究了替位原子对表面吸附原子产额、溅射产额和空位缺陷产额的影响规律,分析了低能沉积过程中沉积原子与基体表面的相互作用机理以及替位原子的作用及其影响规律.研究结果显示:替位原子的存在不仅影响着沉积能量较低时的表面吸附原子的产额与空间分布,而且对沉积能量较高时的低能表面溅射过程和基体表面空位的形成产生重要影响.替位原子导致的表面吸附原子产额、表面原子溅射以及空位形成的变化与替位原子的质量密切相关,质量较小的替位原子导致择优溅射以及溅射阈值的降低.此外,根据二体碰撞模型和载能原子的反射机理探讨了低能沉积过程中沉积原子与基体表面的相互作用机理.

The deposition process of low-energy Pt atoms on Pt （111） surface doped with substitutional impurity Cu, Ag, Au, Ni, or Pd was studied by using molecular dynamics simulation. The atomic interaction potentials with the embedded atom method （EAM） were applied in the simulation. The effects of substitutional impurity on the adatom yield, sputtering yield, and vacancy yield have been observed and summarized. We found that substitutional impurity considerably affects the adatom yield, sputtering yield, and vacancy yield. The main reasons influencing the interaction between low-energy atoms and Pt （111 ） surfaces are the kinetic energy of incident atoms and the mass of substitutional impurity. The light substitutional atoms induced the preferred sputtering of substitutional impurity. A model based the binary collision theory and the atomic reflection mechanism by the substrate is suggested to describe the low-energy deposition process.