中文摘要：

基于非接触式原子力显微镜针尖扫描成像机理，应用分子动力学方法采用非刚性针尖-表面原子团簇相互作用模型，模拟超低温环境下，非接触式原子力显微镜单晶硅针尖扫描单晶硅（111）-（7×7）表面成像过程。仿真计算采用两种原子间经验势函数描述针尖-表面原子间相互作用，两种晶向针尖末端模型都实现了对单晶硅（111）-（7×7）表面原子级分辨率仿真成像，在某些超原子级分辨率仿真图像中在单晶硅（111）-（7×7）表面Adatom原子位置出现了的双月牙峰形结构，模拟计算与成像试验文献中得到的图像基本一致。同时对采用确定的势函数及确定的晶向针尖末端，实现稳定成像的扫描针尖一表面距离进行讨论。扫描过程中针尖和被测表面形貌轻微改变，对扫描成像结果影响不大。

英文摘要：

Based on the non-contact atomic force microscopy （nc-AFM） imaging principle, molecular dynamics method is used for modeling non-rigid silicon tip-surface atomic-cluster interaction. With the model, in ultra low temperature environment, the imaging process .of AFM tip on monocrystalline reconstructed silicon （1 t 1）-（7~7） surface is investigated. Two kinds of potential function is adopted to describe the tip-surface interaction. The atomic resolution imaging of monocrystalline silicon （111）-（7×7） surface is obtained by using two kinds of termination tips with various crystal planes. The simulation results show that distinct substructure （two crescents） images of individual Adatom on silicon （11 1）-（7×7） surface are obtained in some subatomic simulated images, which validates the experimental results. Furthermore, the distance between tip and surface in stable imaging conditions is discussed with certain potential and tip termination. It is shown that the deformations of tip and surface are slight during scanning process, the inflence of which on the imaging effect can be neglected.