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arXiv 1412.7271cond-mat.mtrl-scicond-mat.mes-hall
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石墨烷的电子和光学性质

Electronic and optical properties in graphane

M. H. Lee, H. C. Chung, J. M. Lu, C. P. Chang, M. F. Lin

摘要:

我们发展了紧束缚模型来研究石墨烷的电子和光学性质。碳原子和氢原子之间的强sp3化学键导致了特殊的能带结构,从而导致了丰富的光激发。吸收光谱几乎不依赖于电极化的强度方向。在抛物带的极值点和鞍点处出现了大量的肩状结构和吸收峰。阈值光激发,只与2 px和2 py轨道的碳原子,揭示了在肩结构在?3.5 EV.第一个对称吸收峰出现在~11 eV处,对应于由于碳2 pz轨道和H 1 s轨道相当大的杂化而产生的能带。此外,在较高频率处的一些吸收峰指示2s和1 s轨道的成键。这些结果与sp2石墨烯系统的结果形成鲜明对比。

英文摘要:

We develop the tight-binding model to study electronic and optical properties of graphane. The strong sp3 chemical bondings among the carbon and hydrogen atoms induce a special band structure and thus lead to the rich optical excitations. The absorption spectrum hardly depends on the direction of electric polarization. It ex- hibits a lot of shoulder structures and absorption peaks, which arise from the extreme points and the saddle points of the parabolic bands, respectively. The threshold op- tical excitations, only associated with the 2px and 2py orbitals of the carbon atoms, are revealed in a shoulder structure at ?3.5 eV. The first symmetric absorption peak, appearing at ~11 eV, corresponds to energy bands due to the considerable hybridiza- tion of carbon 2pz orbitals and H 1s orbitals. Also, some absorption peaks at higher frequencies indicate the bonding of 2s and 1s orbitals. These results are in sharp contrast to those of the sp2 graphene systems.

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