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运用紧束缚能带理论,研究拉伸形变下BC3纳米管的能带结构.研究表明:随着拉伸和压缩强度的不断增加,BC3纳米管的导带能级和价带能级逐渐靠近,最终发生能带交叠.压缩形变下能带的交叠程度可达0.5eV,而拉伸形变下只有0.2eV.对于扶手椅型BC3纳米管,随着拉伸和压缩的不断增加,BC3纳米管首先由直接半导体转化为间接半导体,进而发生能带的交叠,表现出金属性.在无形变时,扶手椅型BC3纳米管是一种很不稳定的直接跃迁窄带半导体,轻微的压缩形变(et=-0.003)都可以使其转化为间接半导体.对于锯齿型BC3纳米管,由于存在平坦的导带和价带,轻微的拉伸和压缩形变会使原来全波矢允许的直接跃迁变为只允许一个波矢的直接跃迁.
The energy band structure of BC3 nanotubes under tensile deformation was studied by using the tight binding band theory.The results show that the conduction band and valence band energy levels of BC3 nanotubes gradually approach with the increase of tensile strength and compressive strength, And finally the overlap of energy bands is observed.The energy band of the compressive deformation is up to 0.5eV and the tensile deformation is only 0.2eV.For the armchair type BC3 nanotubes, with the increase of tension and compression, BC3nm The tubes first transform from direct semiconductors to indirect semiconductors, which in turn lead to overlap of energy bands, showing metallicity.In armless BC3 nanotubes, a very unstable direct-transition narrow-band semiconductor with a slight compression set (et = -0.003) can be converted into indirect semiconductors.For the serrated BC3 nanotubes, due to the existence of flat conduction band and valence band, slight stretching and compression deformation will make the original full wave vector allows direct transition change To allow only one wave vector direct transition.