Third nearest neighbor parameterized tight binding model for graphene nano-ribbons
Third nearest neighbor parameterized tight binding model for graphene nano-ribbons
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DOI：
10.1063/1.4994771
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发表时间：
2017-02
期刊：
影响因子：
1.6
通讯作者：
V. Tran;J. Saint-Martin;P. Dollfus;S. Volz
中科院分区：
文献类型：
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作者：
V. Tran;J. Saint-Martin;P. Dollfus;S. Volz
现有的紧密结合模型可以很好地再现二维石墨烯片的从头算带结构。对于石墨烯纳米带（gnr），目前的紧密结合参数集可以成功地描述所有扶手椅型gnr的半导体行为。然而，他们仍然不能准确地再现与群速度和电子有效质量直接相关的能带斜率。在此工作中，密度泛函理论和紧结合计算都进行了，并引入了一组新的紧结合参数，直到第三近邻，包括重叠项。用该模型得到的结果与密度泛函理论的预测在带状结构的大多数情况下非常吻合，即使在高能区域也是如此。此外，从密度泛函理论的结果可以看出，该集合可以诱导电子-空穴不对称。不同宽度的扶手椅缎带也获得了相关的结果。
The existing tight binding models can very well reproduce the ab initio band structure of a 2D graphene sheet. For graphene nano-ribbons (GNRs), the current sets of tight binding parameters can successfully describe the semi-conducting behavior of all armchair GNRs. However, they are still failing in reproducing accurately the slope of the bands that is directly associated with the group velocity and the effective mass of electrons. In this work, both density functional theory and tight binding calculations were performed and a new set of tight binding parameters up to the third nearest neighbors including overlap terms is introduced. The results obtained with this model offer excellent agreement with the predictions of the density functional theory in most cases of ribbon structures, even in the high-energy region. Moreover, this set can induce electron-hole asymmetry as manifested in results from density functional theory. Relevant outcomes are also achieved for armchair ribbons of various widths as wel...