Circular dichroism (CD) of a doped carbon nanotube is calculated as a function of wavelength for several values of the Fermi energy. In the calculation of CD, we consider the so-called depolarization effect by taking account of the dielectric function that suppresses or enhances the electric field inside the undoped or doped nanotube, respectively. Because of the induced electric current of the carriers, the CD of a doped carbon nanotube becomes much larger than that of an undoped nanotube when we select the light-propagating direction parallel to the nanotube axis. The sign of CD changes for enantiomer pair of nanotubes or for type-I and type-II semiconductor nanotubes or by changing the Fermi energy, which is useful for identifying nanotubes in the device.

中文翻译：

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掺杂碳纳米管的圆二色性

掺杂碳纳米管的圆二色性 (CD) 被计算为几个费米能量值的波长函数。在计算 CD 时，我们分别通过考虑抑制或增强未掺杂或掺杂纳米管内部电场的介电函数来考虑所谓的去极化效应。由于载流子的感应电流，当我们选择平行于纳米管轴的光传播方向时，掺杂碳纳米管的 CD 变得比未掺杂纳米管的 CD 大得多。对于纳米管对映体对或 I 型和 II 型半导体纳米管或通过改变费米能量，CD 的符号会发生变化，这对于识别设备中的纳米管很有用。