本論文用tight-binding method來研究多層AB堆疊石墨在電場下的效應。我們發現了在少層能帶會產生能隙，而在多層能帶會重疊，隨著層數的增加，重疊的範圍越大。多層石墨加上電場後的態密度與少層相比也有很大的差別，多層能帶會擴散開來，造成低能處態密度上升幅度比少層大。我們還分析了費米能上態密度隨電場和隨層數的變化，最後再討論多層的吸收光譜。

I use the tight-binding method to study the effect of AB-stacked graphite in the electric field. We found that the energy band will produce the energy gap in few-layers, and overlap in multi-layers. The overlap will become wider with the increased number of layers. The density of states of multi-layer graphene is very different compared to few-layers, the energy band will spread up and the density of states will become larger than few-layers. We also analyzed the the density of states on the Fermi energy with the changes of the electric field and the number of layers. Finally, we discuss the absorption spectra.

[1] K. S. Novoselov, A. K. Geim, S. V. Morozov, D. Jiang, Y.Zhang, S. V. Dubonos, I. V. Grigorieva, and A. A. Firsov, Science 306, 666（2004）
[2] K. S. Novoselov, E. McCann, S. V. Morozov, V. I. Fal’ko, M. I.Katsnelson, U. Zeitler, D. Jiang, F. Schedin, and A. K. Geim,Nat. Phys. 2, 177（2006）
[3] B. Partoens and F. M. Peeters, Phys. Rev. B 74, 075404（2006）
[4] M. Koshino, Phys. Rev. B 81, 125304（2010）
[5] S. B. Kumar and J. Guo, Appl. Phys. Lett. 98, 222101（2011）
[6] D. D. L. Chung, J. Mater. Sci. 37, 1475（2002）
[7] M. Araidai, Y. Nakamura, and K. Watanabe, Phys. Rev. B 70, 245410（2004）
[8] C. P. Chang, Y. C. Huang, C. L. Lu, J. H. Ho, T. S. Li, and M. F. Lin, Carbon 44, 508（2006）
[9] C. L. Lu, C. P. Chang, Y. C. Huang, R. B. Chen, and M. L. Lin, Phys. Rev. B 73, 144427（2006）
[10] G. Grosso and G. P. Parravicini “Solid State Physics”（2000）
[11] W. Zhu, D. Neumayer, V. Perebeinos, and P. Avouris, Nano Lett. 10, 3572（2010）