Structure sensitivity of electronic transport across graphene grain boundaries
Structure sensitivity of electronic transport across graphene grain boundaries
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DOI：
10.1103/physrevb.98.155432
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发表时间：
2018-10
影响因子：
3.7
通讯作者：
D. Perera;J. Rohrer
中科院分区：
文献类型：
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作者：
D. Perera;J. Rohrer
通过大规模合成方法生长的石墨烯通常含有晶界。它们可以强烈影响石墨烯的电子和机械性能，并且有望利用它们来设计电子元件和传感器。在这里，我们考虑半导体石墨烯双晶，并使用密度泛函理论结合非平衡格林函数方法研究晶界结构变化如何影响电子传输。我们发现这些双晶中传输间隙的大小不会因结构变化而改变。然而有趣的是，传输间隙之外的电子传输对晶界的改变非常敏感。我们表明，可以在弹道输运近似中并通过检查能量动量空间中解析的电子态密度来理解这些结果。我们的研究结果表明，石墨烯双晶的电子响应不仅可以通过晶粒取向错误来控制，还可以通过晶界结构的操纵来控制。
Graphene grown by large-scale synthesis methods usually contains grain boundaries. They can strongly affect the electronic and mechanical properties of graphene and it is promising to exploit them for the design of electronic components and sensors. Here, we consider semiconducting graphene bicrystals and study how grain boundary structure variations influence electron transport using density functional theory in conjunction with the nonequilibrium Green function method. We find that the size of the transport gap in these bicrystals is not changed by structure variations. Interestingly however, electron transport outside the transport gap is very sensitive to modifications of the grain boundary. We show that these results can be understood within the ballistic transport approximation and by inspecting the electronic density of states resolved in energy-momentum space. Our findings suggest that the electronic response of graphene bicrystals can be controlled not only by grain misorientation but also by manipulation of the grain boundary structure.