Dirac Fermions in Graphene Nanostructures: Edge Effects on Spectral Density and Quantum Transport
Dirac Fermions in Graphene Nanostructures: Edge Effects on Spectral Density and Quantum Transport
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石墨烯纳米结构中的狄拉克费米子：对光谱密度和量子传输的边缘效应
DOI：
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发表时间：
2011
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通讯作者：
J. Wurm
中科院分区：
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作者：
J. Wurm
近年来，制造和研究石墨烯基纳米结构的能力不断增强。此外，在石墨烯系统中实现相干弹道输运机制方面也取得了巨大进展。这些进展需要对弹道石墨烯纳米结构的电子特性进行通用理论描述和分析，特别是考虑到与系统边界相关的影响。在本论文中，我们提供了一种关于状态谱密度和这些系统的量子传输特性的边缘效应的分析理论，将半经典方法扩展到石墨烯的情况。结果表明，系统边缘特性对频谱和电导有很大影响。数值紧束缚模拟支持这些分析预测。最后，提出了石墨烯纳米带的数值研究，表明边缘散射也可以在弱无序系统中对量子干涉效应产生重要影响。
In recent years, the ability to fabricate and investigate graphene-based nanostructures has been increasing constantly. In addition, great progress has been made towards reaching the coherent ballistic transport regime in graphene systems. These developments call for a generic theoretical description and analysis of the electronic properties of ballistic graphene nanostructures, in particular in view of effects related to the system boundaries. In this thesis we provide an analytical theory of edge effects on the spectral density of states and the quantum transport properties of these systems, extending semiclassical approaches to the case of graphene. It is shown that the characteristics of the system edges have strong impact on spectrum and conductance. Numerical tight-binding simulations support these analytical predictions. Finally, numerical studies of graphene nanoribbons are presented, which show that edge scattering can have important consequences on quantum interference effects also in weakly disordered systems.