低能Cu_6团簇在Cu(001)表面和Au(001)表面沉积的分子动力学模拟研究  

MOLECULAR-DYNAMICS SIMULATIONS OF LOW-ENERGY Cu_6 CLUSTER DEPOSITION ON Cu(001) AND Au(001) SURFACES

作　　者：徐毅[1] 潘正瑛[2,3] 王月霞[2] 

机构地区：[1]中国科学院上海冶金研究所离子束开放实验室 [2]复旦大学现代物理研究所三束材料改性国家重点实验室 [3]中国科学院上海冶金研究所离子束开放实验室,上海201800

出　　处：《物理学报》2001年第1期88-94,共7页Acta Physica Sinica

基　　金：国家自然科学基金!(批准号 :19875 0 11);中国工程物理研究院院外基金资助的课题&&

摘　　要：采用分子动力学方法和混合的Finnis Sinclain势得到了Cu6团簇的最稳定结构———正八面体结构 .模拟了此结构的Cu6团簇在入射能量 (Ein)范围为 0～ 30eV/原子下与Cu(0 0 1)和Au(0 0 1)表面皮秒 (ps)级时间内的相互作用 .计算结果表明在此能量范围内 ,由于荷能团簇原子与表面的相互作用 ,团簇原子由原来的正八面体Cu6结构演变为fcc结构沉积在衬底表面 .随着Ein的增加 ,团簇原子的穿透深度及与表面原子的交换增加 .到能量增加至一阈值 ,衬底表面观察到空位及间隙子损伤 .与Cu表面相比 ,Cu6在Au表面的损伤阈能略高 .得出团簇原子在表面的再构是在很短的时间 (ps量级 )内发生 ,在该时间范围级联碰撞对团簇再构起主要作用 .本工作支持相关的实验结果 ,低能团簇束沉积 (LECBD)有利于纳米表面的形成 ,进而改变团簇沉积能量 ,可控制表面纳米薄膜的结构 .In this paper, the deposition of Cu-6 cluster with a stable octahedral structure on Cu(001) and Au(001) surfaces in tenth of picoseconds is investigated by molecular-dynamics simulations, in which the Finnis-Sinclain potential is used to describe the interactions between copper and gold atoms. The incident energy of the cluster ranges from 0 to 30 eV per atom. By taking 'snapshots' and analyzing the energy partition during the deposition process, it is found that the cluster atoms could rearrange themselves from the original octahedral structure into a fee structure and eventually form an epitaxial layer. The penetration depths of the cluster atoms increase with the impact energy. The substrate suffers damages when the impact energy is increased over a threshold value. Compared with copper surface I the energy threshold for gold surface is a little higher than that for copper surface. The simulations also show that the reconstruction. of cluster atoms on surface is completed in a very short time (a few picoseconds), and during which the collision cascade plays an important role in the cluster reconstruction. Our simulation supports the related experimental results that the low energy cluster beam deposition (LECBD) is favourable for the formation of the nanostructured thin films, which can be controlled by varying the incident energy of clusters.

关 键 词：分子动力学 低能团簇 金属表面 沉积 薄膜 

分 类 号：O481[理学—固体物理]