轴平行磁场中金属性纳米碳管的电子平均自由程公式

A Universal Expression of the Electron Mean Free Path for Metallic Carbon Nanotubes in an Axial Magnetic Field

利用纳米碳管的对称性,提出了金属带模型。将纳米碳管周围环境引起的无序杂质散射势作为微拢引入模型哈密顿量中,推导出了轴平行磁场中金属性纳米碳管的电子平均自由程公式。结果表明,由于金属管在费米面附近具有固定的后散射通道数,且任意一金属带在费米面附近的后散射态密度随管径增大而减小,从而导致金属管的电子平均自由程及局域化长度随管径增大而增大。

By using symmetries of carbor nanotubes,a band model for metallic carbon nanotubes in an axial magnetic field has been obtained.The effects of disorder,which is produced by interactions between the tube and its environment,are incorporated in the model as a perturbation.Then an expression of the electron mean free path (1) is derived.Unlike normal metallic wires, the 1 of metallic nanotubes incrms with their diameter.The reason is that in metallic nanotubes the open conduchon channels are fixed while the density of the back scattered states at Fend level for a metallic band decreases with the tubular diameter.