论文标题
双壁碳纳米管中的带结构和管间光学过渡
Band structure and inter-tube optical transitions in double-walled carbon nanotubes
论文作者
论文摘要
通常，在双壁碳纳米管（DWCNTS）的光谱中，层之间的弱范德华耦合仅导致过渡能相对于原始的单壁纳米管的值而言，其值仅导致其值。但是，最近的结果表明，DWCNT（12,11）@（17,16）的瑞利频谱包含其他峰。使用紧密的结合近似，我们证明在特定的DWCNT中，层间耦合可以稍微修改原始纳米管的带状结构，以使得非常规的管间电子过渡成为可能，并且在DWCNT光学谱中出现了其他峰。除了最近发表的情况外，我们还使用有关DWCNT中118个光学转变的已知实验数据，我们揭示了另外六个具有管间跃迁的DWCNT，并获得了允许它们的几何选择规则。在几十个DWCNT中，我们的方法产生了接近实验观察到的电子跃迁的能量，并且可能对这种型纳米管的结构鉴定有用。
Usually, in optical spectra of double-walled carbon nanotubes (DWCNTs) weak van der Waals coupling between the layers leads only to a small shift of transition energies with respect to their values in pristine single-walled nanotubes. However, recent results have shown that the Rayleigh spectrum of the DWCNT (12,11)@(17,16) contains additional peaks. Using the tight binding approximation, we demonstrate that in specific DWCNTs the interlayer coupling can slightly modify the band structure of pristine nanotubes in such a way that the unconventional inter-tube electronic transitions become possible and additional peaks in the DWCNT optical spectrum appear. Using the known experimental data on 118 optical transitions in DWCNTs, in addition to the recently published case we reveal six more DWCNTs with inter-tube transitions and obtain geometrical selection rules permitting them. In few dozens of DWCNTs our approach yields the energies of electronic transitions close to the experimentally observed ones and may be useful for structural identification of this-type nanotubes.
