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arXiv 1303.6876cond-mat.mes-hall
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双层石墨烯中的四带隧穿

Four band tunneling in bilayer graphene

B. Van Duppen, F. M. Peeters

摘要:

通过矩形势垒和pn结的电导,透射和反射概率得到双层石墨烯考虑到四个频带的能谱。我们已经评估了斜跳参数γ3和γ4对这些性质的重要性,并表明当能量E>γ1/100时,它们的影响可以忽略不计。对于高能量的传播存在两种模式,我们调查这些模式之间的散射。对于垂直入射,两种传播模式是解耦的,它们之间的散射是禁止的。这扩展了赝自旋的概念内定义的两个带近似到一个四带模型,并对应于(反)对称性的波函数下的平面镜像。新的传输共振被发现,出现在电导的两个频带近似中不存在的尖锐的峰值。向系统施加层间偏压:1)破坏赝自旋结构,2)打开导致电导中抑制透射的明显特征的带隙,以及3)破坏透射和反射中相对于法向入射的角对称性。

英文摘要:

The conductance, the transmission and the reflection probabilities through rectangular potential barriers and pn-junctions are obtained for bilayer graphene taking into account the four bands of the energy spectrum. We have evaluated the importance of the skew hopping parameters γ3 and γ4 to these properties and show that for energies E>γ1/100 their effect is negligible. For high energies two modes of propagation exist and we investigate scattering between these modes. For perpendicular incidence both propagation modes are decoupled and scattering between them is forbidden. This extends the concept of pseudospin as defined within the two band approximation to a four band model and corresponds to the (anti)symmetry of the wavefunctions under in-plane mirroring. New transmission resonances are found that appear as sharp peaks in the conductance which are absent in the two band approximation. The application of an interlayer bias to the system: 1) breaks the pseudospin structure, 2) opens a bandgap that results in a distinct feature of suppressed transmission in the conductance, and 3) breaks the angular symmetry with respect to normal incidence in the transmission and reflection.

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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