石墨烯的位错研究

发布时间：2018-04-21 02:18

本文选题：石墨烯 + 位错　；参考：《浙江理工大学》2017年硕士论文

【摘要】：石墨烯是一种由碳原子组成的密排六方二维平面薄膜,具有良好的电热传导率,超高的透光率,摩擦系数小等优良性质,应用前景广泛.实际中石墨烯不都是完美的,存在吸附原子,空位,位错等缺陷,这些缺陷会对石墨烯的力学,电学,光学等性质产生影响.分子模拟方法是纳米材料计算中的一种主要方法,在物理,化学,材料等领域的研究中起着重要作用.由于石墨烯的尺寸非常小,处在纳米量级,使用分子模拟方法可以从原子级别探究石墨烯的各种性质,如石墨烯的结构特征,原子运动细节等.本文采用分子模拟方法,研究石墨烯的结构特性.键级势是基于量子力学计算势能的一种半经验势,兼具第一性原理模拟的准确度和分子模拟的速度,是在常用的半经验势Tight-Binding(TB)基础上建立起来的,能够反应化学键的变化,而且计算快速准确.因此本文采用键级势研究石墨烯,计算了完美石墨烯的势能,结果与文献一致.根据石墨烯的键级势,本文给出了每个原子的受力分析.数值实验表明完美石墨烯的确处于平衡状态,受力几乎为零.另外,本文对石墨烯中的位错进行了初步研究,用Peierls-Nabarro模型,给出了Glide位错和Shuffle位错的生成方法,为进一步研究石墨烯的位错性质及其运动打下了良好的基础.
[Abstract]:Graphene is a hexagonal planar thin film composed of carbon atoms. It has good electrothermal conductivity, high transmittance and low friction coefficient. In practice, graphene is not perfect. There are some defects such as adsorption atoms, vacancies, dislocations and so on. These defects will affect the mechanical, electrical and optical properties of graphene. Molecular simulation is one of the main methods in the calculation of nanomaterials, which plays an important role in the research of physics, chemistry, materials and so on. Because the size of graphene is very small and it is in the nanometer order, the molecular simulation method can be used to explore the various properties of graphene from the atomic level, such as the structure characteristics of graphene, the details of atomic movement and so on. In this paper, the molecular simulation method is used to study the structural characteristics of graphene. Bond order potential is a semi-empirical potential based on quantum mechanics to calculate potential energy. It has both the accuracy of first-principle simulation and the velocity of molecular simulation. It is based on the commonly used semi-empirical potential Tight-BindingTB. it can react the change of chemical bond. And the calculation is fast and accurate. In this paper, the potential energy of perfect graphene is calculated by using bond potential. The results are in agreement with the literature. According to the bond order potential of graphene, the stress analysis of each atom is given in this paper. Numerical experiments show that the perfect graphene is in equilibrium and the force is almost zero. In addition, the dislocations in graphene are preliminarily studied in this paper. By using the Peierls-Nabarro model, the generation methods of Glide dislocations and Shuffle dislocations are given, which lays a good foundation for further study on the dislocation properties and movement of graphene.
【学位授予单位】：浙江理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O613.71

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