【作者】 朱卫娟；

【导师】 颜晓红；

【作者基本信息】 南京航空航天大学 ， 凝聚态物理， 2008， 硕士

【摘要】 碳纳米结构包括碳纳米管,单层石墨片以及含缺陷的单层石墨片等众多的奇特结构,这使得它具有优良的性能并成为近年来材料界以及凝聚态物理研究的前沿和热点。本文利用基于密度泛函的第一性原理软件CASTEP,研究了正六边形的硅纳米管在碳纳米管中的稳定性,几何结构,能带特征以及含缺陷的单层石墨片对金原子的吸附作用。具体安排如下:第一章,介绍了碳纳米管以及单层石墨片的研究背景,并对它们的结构特征,制备方法和物理性能做了一个综述性的介绍。第二章,详细地介绍了基于密度泛涵理论(DFT)的第一性原理计算软件CASTEP,包括它的结构,使用和功能。第三章,探讨了硅纳米管在碳纳米管中的稳定性,几何结构以及能带图。硅的正六边形的管状结构吸入C(7,7),C(8,8)中时需要吸收热量,而将其置入C(9,9)中是释放能量。并且当硅纳米管与碳纳米管的相对位置发生变化时,相互作用表现出震荡或者周期性的变化规律。分析了能带随相互作用的变化。第四章,研究了含缺陷的石墨片对金原子的吸附作用。首先讨论了单层石墨片中单原子缺陷,双原子缺陷,以及SW缺陷的形成能;其次分析了这三种缺陷对金原子吸附作用的强弱。得到了缺陷结构含有的悬挂键越多对金原子的吸附作用越强的结论。发现电子从电荷转移量以及电荷密度分布图分析了吸附机制。电子从金原子转移到了石墨片。第五章,对工作做了一个总结,以及对于未来工作的展望。更多还原

【Abstract】 Carbon material has been a hotspot and frontier of material research and condensed matter physics in recent years because of its mesoscopic dimension and novel physical and chemical properties. In this thesis, we investigate the stability, geometrical structures and electronic energy band of hexagonal silicon nanotube (SiNT) confined inside carbon nanotubes based on first-principle calculations. In the meanwhile, we also study the gold atoms on a single layer graphite surface with different defects. The thesis is organized as follows:In Chapter 1, the background of carbon nanotubes and graphite are introduced, which includes their geometrical structures, making method and physical properties.In Chapter 2, the first-principle computation software CASTEP, which is based on the Density Function Theory (DFT), is introduced. The program structure, application process and computation function are concluded.In Chapter 3, the stability, geometrical structures and electronic energy band of hexagonal silicon nanotube (SiNT) confined inside carbon nanotubes are studied. The results show that the encapsulating process of SiNT is exothermic in (9, 9) carbon nanotube while endothermic in (8, 8) and (7, 7) carbon nanotubes. We discuss the variation of total energy as the SiNT rotates around its axis inside carbon nanotubes. Band structures are also analyzed.In Chapter 4, gold atoms on a single layer graphite surface with defects are studied. First of all, the formation energy for single vacancy, multi-vacancies, SW are calculated, then, the interaction between Au atoms and graphite with defects is discussed. We found the more dangling bonds graphite has, the stronger the interaction is with Au. Charger transfer and electronic density can illuminate this situation. Charges transfer to graphite.In Chapter 5, a final conclusion is drawn for all the results obtained as well as some prospects are given.更多还原