单壁碳纳米管的电子速度及有效质量

Electronic Velocity and Effective Mass of the Single-walled Carbon Nanotubes

利用单壁碳纳米管(SWCNTs)能量色散关系,计算了最低导带的电子速度和有效质量,重点讨论了SWCNTs中最低导带电子速度和有效质量与波矢及管径大小的关系.结果表明,半导体型锯齿SWCNTs的电子速度和有效质量与其结构参量(管径)有直接的关系.各种椅型SWCNTs(金属型)和金属型锯齿SWCNTs最低导带电子速度和有效质量随波矢的变化规律分别相同,各种半导体型锯齿SWCNTs最低导带电子速度和有效质量随波矢的变化规律则有明显差别.这意味着在低偏压下,不同管径的椅型SWCNTs和金属型锯齿SWCNTs输运性能相同,而各种不同管径半导体型锯齿SWCNTs输运性能有明显差别.

Based on energy dispersion relation of the single-walled carbon nanotubes （SWCNTs）, the electronic velocity and effective mass of the lowest conduction band for the SWCNTs were computed, and the relation of the electronic velocity and effective mass with the wave vector and diameters of the SWCNTs were discussed emphatically. The calculated results show that the electronic velocity and effective mass significantly depend on the structure parameter of the semiconducting zigzag-SWCNTs such as their diameter. The electronic velocity and effective mass of the lowest conduction band for various armchair （always metallic） SWCNTs and metallic zigzag SWCNTs have the same changing curves versus the wave vector, but for various semiconducting zigzag-SWCNTs the electronic velocity and effective mass of the lowest conduction band have different changing curves versus the wave vector. This means that under the low bias voltage, various metallic zigzag-SWCNTs and armchair SWCNTS with different diameters have the same transport properties, while the semiconducting zigzag-SWCNTs with different diameters have different transport properties.