递归格林函数方法研究石墨烯纳米带电子输运性质

发布时间：2018-04-14 06:38

本文选题：石墨烯纳米带 + 电子输运性质　；参考：《西南科技大学》2015年硕士论文

【摘要】：石墨烯表现出许多非同寻常的物理性质而备受关注,比如：反常量子Hall效应,Klein遂穿,最小电导率等。它很可能替代硅而成为制备下一代光电器件的首选材料,因此对石墨烯材料的研究具有很高的理论和实际应用价值。由于实验上很难制备高质量、无缺陷的石墨烯,因此对缺陷石墨烯的研究成为热点。本论文采用紧束缚近似结合递归格林函数方法,计算了完美的石墨烯纳米带电子能带结构和输运性质,研究了缺陷石墨烯纳米带的电子结构与输运性质,得到以下结论：1、对边界吸附和边界空位两种情况的金属性石墨烯纳米带的研究表明,边界吸附和边界空位对体系电导有很明显的影响。随着缺陷浓度的增大,体系电导受到的压制就越明显,同时,出现一个电导沟。研究发现,电子态的局域性导致了电导沟的产生。2、计算了体空位缺陷石墨烯纳米带的电子结构和输运性质,结果表明,电导曲线对体空位的依赖性同样很敏感。当体系有一个单原子空位时,发现有电导沟存在,且量子化的电导台阶平滑化了。当体系存在两个体空位时,我们发现纳米带的电导曲线在低能时存在共振透射峰,且透射峰的数目和两个体空位间的距离密切相关,即,当距离每增加约三个超原胞时,透射峰就会增加一个。这种奇特的物理性质可能为实验提供指导。
[Abstract]:Graphene shows many unusual physical properties, such as anomalous quantum Hall effect Klein penetration, minimum conductivity and so on.It is likely to replace silicon as the preferred material for the preparation of next generation optoelectronic devices. Therefore, the study of graphene materials has a high theoretical and practical application value.Because it is difficult to prepare high-quality and non-defect graphene experimentally, the research of defective graphene has become a hot topic.In this paper, the tight-binding approximation combined with the recursive Green's function method is used to calculate the electron band structure and transport properties of the perfect graphene nanoribbons, and the electronic structure and transport properties of the graphene nanoribbons with defects are studied.The following conclusions are obtained: 1. The study of gold graphene nanobelts with boundary adsorption and boundary vacancy shows that the boundary adsorption and boundary vacancy have a significant effect on the conductance of the system.With the increase of defect concentration, the compaction of the conductance of the system is more obvious, at the same time, there is a conductivity ditch.It is found that the localization of electronic states leads to the generation of conductance grooves. The electronic structure and transport properties of bulk vacancy defects graphene nanobelts are calculated. The results show that the conductance curves are also sensitive to bulk vacancies.When there is a single atomic vacancy in the system, a conductivity channel is found and the quantized conductance step is smoothed.When there are two bulk vacancies in the system, we find that the conductance curve of nanobelts has a resonance transmission peak at low energy, and the number of transmission peaks is closely related to the distance between the two voids, that is, when the distance increases by about three supercells,The transmission peak will increase by one.This peculiar physical property may provide guidance for the experiment.
【学位授予单位】：西南科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ127.11;TB383.1

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