【摘要】 针对三种结构类型的单壁碳纳米管的电子结构和声子谱,采用基于密度泛函理论的第一性原理以及CASTEP软件进行了理论计算。在完成建模和结构优化的基础上,对扶手椅型(10,10)、锯齿型(6,0)和螺旋型(4,2)单壁碳纳米管的电子能带及电子态密度、声子谱及声子态密度进行了理论计算,并对计算结果进行了理论分析。结果表明:(10,10)及(6,0)单壁碳纳米管无能量禁带,它们属于金属型管;而(4,2)单壁碳纳米管有一宽度为0.85 eV的能量禁带,它属于半导体型管。以上计算结果与用其它判据给出的结论相一致。在以上三种管的声子谱中,它们依次有120条、72条和168条(其中有简并情况)色散曲线,并且它们的声子态密度依次在频率41.88 THz、23.95THz和23.43 THz处出现最大值,即在这些频率附近的格波最多。这一计算结果与物理规律是一致的。更多还原

【Abstract】 Electronic structure and phonon spectrum of three structure types of single-wall carbon nanotubes( SWNTs) were theoretically calculated by the first principles calculations based on density functional theory( DFT) with CASTEP software. The energy band and density of electrons states,phonon spectrum and density of phonon states about( 10,10) armchair,( 6,0) zigzag and( 4,2) spiral SWNTs were calculated on the basis of the completion of modeling and structure optimization in the paper. The calculated results indicated that the SWNTs( 10,10) and( 6,0),which have no energy band gap,are metal-tubes whereas SWNT( 4,2) is a semiconductor tube with an energy band gap of. The above results are consistent with the conclusions given by other criteria. The phonon spectrums of the above three tubes have,respectively,120,72 and 96( contain degeneration) dispersion curves. And their densities of phonon states reach maximum values at the frequencies of 41. 88 THz,23. 95 THz and 23. 43 THz respectively,which means the lattice waves are the most at these frequencies. These results are consistent with the laws of physics.更多还原