Calculation Of Electronic Structure, Phonon Spectra And Young’s Modulus Of Single-walled Carbon Nanotubes

Carbon nanotubes have unique physical properties. It is a important new nano-materials. And also in the field of composite materials, Nano-mechanical, electronic materials, medical facilities it have a wide range of applications.We need to have a better awareness and understanding of the carbon nanotubes’ electronic structure and thermal performance for designing and applications of carbon nanotubes and nano-devices. Therefore, the thesis ‘single-walled carbon nanotubes electronic structure and Phonon spectrum and calculation of modulus’ is of great theoretical significance and value.In this paper, the electronic structures and elastic moduli of three kinds of single walled carbon nanotubes were calculated by using the first principles of density functional theory, and CASTEP.On the basis of completing modeling and structure optimization. We calculate the electron energy band and desity of electronic states, phonon spectrum and phonon density of states, elasticity modulus of(10,10),(6,0),(4,2) single walled carbon nanotubes. The results show that:(10,10) and(6,0) single walled carbon nanotubes have no energy band gaps. Belongs to the metal pipe; and(4,2) single wall carbon nanotubes have a width of 0.85 eV energy band gap, it belongs to the type semiconductor tube. In the above three kinds of tubes of phonon spectra, which in turn has 120, 72 and 96 bands(including the degenerate) dispersion curves, and their phonon density of states in turn in the frequency 41.88 THz, and 23.95.0THz 23.43 THz appeared maximum value that at these frequencies in the vicinity of the lattice wave up.(10,10)(6,0)(4,2) the elastic modulus calculation results are divided into580.762 Gpa 、1046.436Gpa、637.80 Gpa.These results are consistent with the conclusions given by other criteria.The results of this paper provide a useful reference for the relevant theoretical and applied research.