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arXiv 1412.7484cond-mat.mes-hall
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有限长碳纳米管中的两类低能谱

The two classes of low energy spectra in finite carbon nanotubes

Magdalena Marganska, Piotr Chudzinski, Milena Grifoni

摘要:

碳纳米管中的电子具有自旋和轨道自由度。后者是从具有两个不等价狄拉克点的二分石墨烯晶格继承的。在平行磁场中对碳纳米管量子点的几个输运实验中获得的电子光谱经常显示出分配给相反狄拉克谷的谱线的反交叉。到目前为止,这种谷混合已被归因于无序,杂质诱导散射。我们表明,这种效果也可以出现在扶手椅类的超净碳纳米管,它可以完全由边界的存在。相反,在锯齿形类的CNT中,它不发生。这两个根本不同的类的光谱出现,因为不同的对称性的低能量本征态的两种类型的碳纳米管。能级分裂的大小以非单调的方式依赖于所涉及的能级到电荷中性点的距离。

英文摘要:

Electrons in carbon nanotubes (CNTs) possess spin and orbital degrees of freedom. The latter is inherited from the bipartite graphene lattice with two inequivalent Dirac points. The electronic spectra obtained in several transport experiments on CNT quantum dots in parallel magnetic field often show an anticrossing of spectral lines assigned to the opposite Dirac valleys. So far this valley mixing has been attributed to the disorder, with impurity induced scattering. We show that this effect can arise also in ultraclean CNTs of the armchair class and it can be caused solely by the presence of the boundaries. In contrast, in CNTs of the zigzag class it does not occur. These two fundamentally different classes of spectra arise because of different symmetries of the low energy eigenstates of the two types of CNTs. The magnitude of the level splitting depends in a nonmonotonous way on the distance of the involved energy levels from the charge neutrality point.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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