Research On The Interaction Between Carbon Nanotubes/graphite And Other Nanostructures

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.