First-principle analysis on coupling of mechanical and electrical properties in interface region

电子器件和微纳机电系统（MEMS/NEMS）需要各种材料。因此，在材料中存在着许多界面，界面上的材料具有特殊的性质。本研究首先采用第一性原理分子动力学模拟（赝势，平面波基础）研究了铝在（100）面硅衬底上的沉积过程。由于调光器的行上形成的硅表面上，我们研究了两种类型的接口结构。（1）第一层上的铝原子在较暗的行之间形成平行线（2）与其垂直排列的铝原子。由于铝原子之间的键合强度大于铝原子与硅原子之间的键合强度，碳纳米管作为先进器件或MEMS/NEMS中的元件，具有优异的机械/电子性能，受到了研究者的关注。由于它们与其他部件连接，变形发生在界面附近的管中。然后，我们进一步研究了碳纳米管的力学和电学性质的耦合，以探索由于约束而导致的界面附近行为的变化。采用紧束缚模拟径向和轴向载荷。法根据手性，管显示金属或半导体性质下没有外部负载。这项研究表明，这些性质的变化，由于外部负载的变形。

Electronic devices and micro-or nano-electromechanical systems (MEMS/NEMS) require various materials. Thus, there exists many interfaces in then and the material on the interface possesses characteristic property. At first in this study, we have investigated the process of aluminum deposition on silicon substrate with a (100) surface by using the first-principle molecular dynamics simulation (pseudo-potential, basis of plane wave). As the rows of dimmers are formed on the silicon surfaces, we examined two types of the interface structures.(1)The aluminum atoms on the first layer form parallel line between dimmer rows(2)Those align perpendicular to it.The aluminum atoms on the first layer possess broad distribution of electrons. The bond between the aluminum atoms is stronger than that between the aluminum atom and the silicon at the interface.The carbon nano-tubes are getting researcher's attentions because of its excellent mechanical/electronic properties as components in advanced device or MEMS/NEMS. Since they are connected with other components, the deformation takes place in the tube near the interface. Then, we secondary investigated the coupling of mechanical and electronic properties of carbon nano-tubes in order to explore the change in the behavior near the interface due to the constraint. We simulate the radial and axial load by the tight binding. method. Depending on the chirality, the tubes show metallic or semi-conducting properties under no external load. This study reveals that these properties are changed by the deformation due to the external load.