摘 要
　　我們使用SP3 的緊束模型來研究單層碳微管在均勻橫向電場下的電子性質。碳微管的電子特性和曲度效應、幾何結構（如碳微管的半徑、螺旋性的碳微管等）和電場的強度有強烈的相關性。電場能改變能隙、能帶曲度、能帶的簡併度，和邊界態的數目、位置；而且，在某些電場會發生金屬—半導體轉換，這些影響都直接反應在態密度上。一維的能帶結構在態密度上呈現了許多的峰，電場強度能決定態密度峰值的高度、位置，以及峰值的數目，這些預測的結果都能由像是STM和測量光譜等實驗來驗證。

Abstract
　The sp3 tight-binding model is used to study electronic properties of single-walled carbon nanotubes in the presence of the uniform perpendicular electric field. Electronic properties strongly depend on the curvature effect, the geometric structure (radius and chiral angle), and the strength of electric field. The electric field could change energy gap, energy band curvature, the position and the number of edge state, and the state degeneracy. Furthermore, there are semiconductor-metal transitions at certain electric fields. Such effects are directly reflected in density of states (DOS). DOS exhibits a lot of prominent peaks, owing to the one-dimensional energy bands. The number, the position, and the height of pronounced peaks are determined by the field strength. The predicted results could be directly verified by the experimental measurements, such as STM and optical spectroscopy.

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