Elucidation and Control of Surface Electronic and Atomic Processes by the Tip

各种现象都是由扫描探针显微镜中的尖端和样本表面之间的纳米尺度差距诱导的。在它们中，电子和原子的基本过程对基本科学和理论应用的基础是最重要的。这个项目的目的是开发一种理论方法来描述和预测这些过程和澄清它们的基本方面。由于其目的是第一个·原则的递归转移矩阵方法被开发出来，它是非equilibrium开放系统的密度功能理论的扩展。在这种方法中，波浪功能是以分散的波浪形式和隧道尾巴是非常精确地确定的。通过STM、尖端诱导的化学过程、尖端和表面之间的原子转移的方法定量分析，可以从第一个原则研究，并且通过这个方法，接下来的问题就可以研究了。第一个是两个表面之间的微观接触。A sharp onset of the electronic inceraction of sufaces is found and the details of the potential distribution are studied as well as the concept of the local workiunction。The Mechanism of atom extraction by the tip of STM is clarified as follows。当尖端被消极地误导时，电子云被推到尖端尖端的前端。然后，它是在尖端尖端原子和表面原子之间的中间区域累积的。随着负尖端偏差的进一步增加，电子云形成了一个具有表面的桥梁结构，然后一个非常强大的力量在安慰原子上起作用。这种情况是完全依赖于尖端高度和尖端表面材料的。

Various phenomena are induced by the nano-scale gap between the tip and the sample surface in the scanning probe microscopy. Among them the elementaly processes of electrons and atoms are most important both for the fundamental science and for the basis of thechnological applications. The purpose of this projet is to develop a theoretical method to describe and predics these processes and clarify their fundamental aspects. For that purpose the first・principles recursiontransfer matrix method is developped which is an extension of the Density Functional Theory for non-equilibrium open systems. In this method wavefunctions are solved in a scattering wave forms and the tunneling tails are very precisely determined. With the method quntitative analyzes of STM,tip induced chemical processes, atom transfer between the tip and over the surface can be studied from the first・principles.With this method the following problems are studied. The first is the microscopic contact between the two surfaces. A sharp onset of the electronic inceraction of sufaces is found and the details of the potential distribution are studied as well as the concept of the local workiunction.The mechanism of atom extraction by the tip of STM is clarified as follows. When the tip is negatively biased, the electron cloud is pushed cut in front of the tip apex. Then it is accumlated in the interstitial region between the tip apex atom and the surface atom confronted to it. With the further increase of the negative tip bias, the electron cloud forms a bridge structure with the surface, then a very strong force is acted on the suriace atom. The situationis quite dependent on the tip height and the tip surface materials.