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，当时存在多个界面，界面上的材料具有特征属性。本研究首先利用第一性原理分子动力学模拟(赝势，平面波基)研究了(100)面硅衬底上铝的沉积过程。由于在硅表面上形成了两种类型的界面结构：(1)第一层上的铝原子在两个较暗的行之间形成平行线；(2)与其垂直排列。第一层上的铝原子具有广泛的电子分布。铝原子之间的结合比铝原子与硅原子之间的界面结合更强。碳纳米管作为先进器件或MEMS/NEMS中的元器件，由于其优异的力学/电学性能而受到研究人员的关注。由于它们与其他组件连接，因此变形发生在靠近界面的管子中。然后，我们对碳纳米管的力学和电学性质的耦合进行了二次研究，以探索约束对碳纳米管界面附近行为的影响。我们用紧约束来模拟径向和轴向载荷。方法。根据手性的不同，管子在没有外部载荷的情况下表现出金属或半导体性质。研究表明，这些特性会随着外载的变形而发生变化。

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.