Grain boundary structure and migration in graphene via the displacement shift complete lattice
Grain boundary structure and migration in graphene via the displacement shift complete lattice
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DOI：
10.1016/j.actamat.2018.12.030
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发表时间：
2019-03
期刊：
影响因子：
9.4
通讯作者：
Emil Annevelink;E. Ertekin;H. Johnson
中科院分区：
文献类型：
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作者：
Emil Annevelink;E. Ertekin;H. Johnson
我们用位移位移完全晶格中的位错概念来描述石墨烯中的晶界结构和迁移。从拓扑和能量两个方面说明了石墨烯中位移位移、完全晶格位错和晶界扭结的等价性。在拓扑上，晶界扭结和位移位移完全晶格位错都平移了重合格子。通过比较亚稳态原子弹性模型和连续介质弹性模型，建立了能量等价关系，表明弹性理论能很好地描述DSC位错。用DSC位错核半径这一可调参数对连续谱结果与原子学结果进行了拟合。原子学结果表明，低西格玛晶界对晶界运动具有较大的能垒，这与较小核心半径位错的连续谱结果相吻合。在生长的石墨烯中，低西格玛边界的较大能垒与报道的孤立的低西格玛边界的实验结果一致。用统一的模型描述了不同取向的晶界上位错Burgers矢量和拟合芯半径的变化趋势。这一分析为理解石墨烯中的晶界运动提供了一个框架，并可作为设计石墨烯原子结构的基础。
We describe grain boundary structure and migration in graphene using the concept of dislocations in the displacement shift complete lattice. The equivalence of displacement shift complete lattice dislocations and grain boundary kinks in graphene is shown both topologically and energetically. Topologically, a grain boundary kink and a displacement shift complete lattice dislocation both translate the coincident site lattice. The energetic equivalence is established through comparison of atomistic and continuum elasticity models of metastable states to show that DSC dislocations are well-described by elasticity theory. The continuum results are fitted to the atomistic results with one adjustable parameter, the DSC dislocation core radius. The atomistic results reveal that low sigma boundaries have large energy barriers to grain boundary motion, which match continuum results obtained for smaller core radii dislocations. The larger energy barriers for low sigma boundaries are consistent with experimental results reporting isolated, low sigma boundaries in grown graphene. The trends in the dislocation Burgers vector and fitted core radii across grain boundaries of different misorientation are expressed in a unified model. The analysis provides a framework for understanding grain boundary motion in graphene and can serve as a basis for engineering the atomic structure of graphene.