Surface-tip interactions in noncontact atomic-force microscopy on reactive surfaces: Si(111)
Surface-tip interactions in noncontact atomic-force microscopy on reactive surfaces: Si(111)
复制标题
DOI：
10.1103/physrevb.58.10835
复制
发表时间：
1998-10-15
影响因子：
3.7
通讯作者：
Terakura, K
中科院分区：
文献类型：
--
作者：
Perez, R;Stich, I;Terakura, K
采用总能量赝势方法研究了非接触原子力显微镜在Si（111）表面的成像过程。在尖端和表面之间最接近的距离处，在尖端和表面的悬挂键之间开始共价化学键合。位移曲线和表面横向扫描表明，这种相互作用的能量和力的宏观货车范德华相互作用。然而，共价相互作用完全主导了实验中探测的力梯度。因此，这种共价相互作用是负责在反应性表面上获得的原子分辨率，它应该在提高其他系统的分辨率中发挥作用。我们的研究结果提供了一个清晰的理解的一些问题，如（i）在实现稳定的操作实验的难度，（ii）在不同的实验中获得的图像的质量和尖端准备的作用和（iii）最近观察到的力梯度曲线的不连续性。[S0163-1829（98）08336-2]。
Total-energy pseudopotential calculations are used to study the imaging process in noncontact atomic-force microscopy on Si(111) surfaces. At the distance of closest approach between the tip and the surface, there is an onset of covalent chemical bonding between the dangling bonds of the tip and the surface. Displacement curves and lateral scans on the surface show that this interaction energy and force are comparable to the macroscopic Van der Waals interaction. However, the covalent interaction completely dominates the force gradients probed in the experiments. Hence, this covalent interaction is responsible for the atomic resolution obtained on reactive surfaces and it should play a role in improving the resolution in other systems. Our results provide a clear understanding of a number of issues such as (i) the experimental difficulty in achieving stable operation, (ii) the quality of the images obtained in different experiments and the role of tip preparations and (iii) recently observed discontinuities in the force gradient curves. [S0163-1829(98)08336-2].