在這篇論文之中，我們以緊束模型討論了在外加垂直於石墨層的電場下，少層AA及ABC兩種不同堆疊石墨系統的電子和光學性質。這些不同堆疊石墨系統的電子和光學性質將隨著堆疊序列、石墨的層數、鉛直方向(垂直石墨面)的靜電場強度而有著特性上的變化。不論有無電場的作用，在低能附近的AA堆疊石墨吸收光譜都是呈現出肩狀的跳躍結構。在無電場存在時，N層ABC堆疊石墨的吸收光譜有著不一樣的特徵，其呈現出尖峰和跳躍結構。所施加的電場對能帶結構產生影響，像是變化了態能量，改變了副能帶間的空間，產生震盪能帶而且增加了能帶邊緣態。因此，電場調制了吸收光譜，包括產生了新的峰結構，改變了峰的位置和峰的高度。更進一步地，我們可以預期峰結構的頻率很顯著地決定於層數和電場強度。最重要的是，這些預測出的吸收光譜和相關的電子性質可以由光學量測來証實。

Optical properties of the AA- and ABC-stacked few-layer graphites

under application of the electric field (F), perpendicular to the layers, is

explored through the gradient approximation. They are closely related to

the geometric structure (layer number, interlayer interactions and stacking

sequences) and the field strength. In the absence or presence of an electric

field, the low-energy absorption spectra of the AA-stacked few-layer

graphites exhibit the jumping structures. In the absence of an electric field

, the ABC-stacked few-layer graphites show the spectra with the different

feature, including the jumping structures and sharp peaks. The application

of an electric field, F, influences the energy dispersions, e.g., the change

of band feature and subband spacing, the production of oscillating bands ,

and the increases of the band-edge states. As a result, F modifies the

absorption spectra, including the generation of new peaks, the change of

peak position and peak height. Moreover, the frequency of peak is

predicted to be strongly dependent on the layer number and the field

strength. Above all, the predicted absorption spectra and the associated

electronic properties could be verified by the optical measurements.

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