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First-Principles Study Of Carbon Nanoscrolls

Posted on:2012-11-12Degree:MasterType:Thesis
Country:ChinaCandidate:X Q GongFull Text:PDF
GTID:2131330338957742Subject:Theoretical Physics
Abstract/Summary:PDF Full Text Request
Graphene is a hotspot and frontier of materials research and condensed matter physics in recent years. With the rapid development of nanotechnology ,especially upon discovering fullerence, nanotube, and graphene, there exist many possibilities to design and realize molecular devices by using the properties of the nanomaterials. In the rapid development of the experiment, using a variety of theoretical models to explain experimental phenomena and to design electronic devices has become increasingly plays an important role. In this paper, by using based first -principles density functional theory calculation software package CASTEP, geometry structures, electronic structure and stability of carbon nanoscroll, carbon nanotube / carbon nanoscroll materials are investigated.Firstly, an analytical geometrical model for quasi one-dimensional graphene nanomaterials is constructed. The general carbon nanoscrolls model is characterized by an Archimedes spiral line with two construction parameters. A set of analytical expressions are derive d for all the coordinates of carbon atoms in a supercell under a three-dimensional coordinate system.Secondly, the geometric structures, stability and electronic properties of carbon nanoscrolls are calculated by using the first principles density functional calculation package CASTEP. The results show that carbon nanoscrolls are the most stable with the interlayer distance t = 3.4 (A|°). The band structure near the Fermi surface of armchair carbon nanoscrolls is similar to armchair graphene nanoribbons, but the band structure near the Fermi surface of zigzag carbon nanoscrolls is very different to armchair graphene nanoribbons. Further studies showed that the difference band structure of carbon nanoscrolls and graphene nanoribbons are caused by the interaction of atoms, not caused by the curvature effect.Finally, the geometric structure, stability and electronic properties of the model of carbon nanotube / carbon nanoscroll are studied. The results show that carbon nanotube / carbon nanoscroll are the most stable with the initial interlayer distance△r0 = 3.4 (A|°). The band structure and the density of the carbon nanotube / carbon nanoscroll can be considered to be carbon nanotube and carbon nanoscroll superimposed. Further studies show that carbon nanotube / carbon nanoscroll is carbon nanotubes and carbon nanoscroll loose combination, tube and scroll integration between the carbon atoms are not close.In conclusion, we have performed first-principles density functional theory calculations on the properties of carbon nanoscroll, carbon nanotube / carbon nanoscroll. This investigation on the properties of carbon nanoscroll, carbon nanotube / carbon nanoscroll will lay a good theoretical foundation in synthesis and design of these molecular devices of materials in the future.
Keywords/Search Tags:density functional theory, first-principle, carbon nanoscroll, electronic structure
PDF Full Text Request
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