外加轴向磁场下碳纳米管场效应晶体管的电学性质

在紧束缚理论的基础上推导出轴向磁场下碳纳米管的能带公式，研究外加磁场下碳纳米管场效应晶体管的电学特性.说明磁场可使碳管的导电性质在金属型和半导体型之间转变，转变的磁场周期为0.5₀.进一步应用场效应晶体管Natori理论模拟计算了外加磁场对碳纳米管场效应晶体管的电流-电压特性的影响，研究结果显示zigzag管和armchair管的电流随外电压和磁场都有振荡行为，而且两类管的振荡行为有明显差别. 关键词： 碳纳米管 紧束缚理论 费米能 能带结构

Electrical properties of carbon nanotube field-effect transistors in applied axial magnetic field

On the basis of the tight-binding theory，we derived the band structure formula of carbon nanotube field-effect transistors with/without a magnetic field. The results show that the band gap becomes zero periodically with increasing strength of the magnetic field，which indicates that the magnetic field can change the nature of the conductivity of carbon between the metal-type and semiconductor-type with 0.5₀ for the period. Furthermore，by using Natori theory on the field-effect transistor, we studied the influence of applied magnetic field on the current-voltage characteristics of carbon nanotube field-effect transistors. The results show that in the two types of zigzag and armchair carbon tubes the conductivity oscillates with the voltage and the magnetic field and the oscillation behaviors are obviously different for these two types of carbon nanotubes.