Triggering One-Dimensional Phase Transition with Defects at the Graphene Zigzag Edge
Triggering One-Dimensional Phase Transition with Defects at the Graphene Zigzag Edge
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DOI：
10.1021/acs.nanolett.5b04557
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发表时间：
2016-02-01
期刊：
影响因子：
10.8
通讯作者：
Zhao, Jiong
中科院分区：
文献类型：
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作者：
Deng, Qingming;Zhao, Jiong
关于一维 (1D) 系统的一个众所周知的论点是，有限温度下的一维相变不可能存在，尽管这一概念取决于相互作用范围、外部场和周期性等条件。因此，一维系统通常具有随机波动，并会出现内在的畴壁，从而在转变过程中自然地带来无序。在这里，我们介绍了一个真正的一维系统，其中人为创建的缺陷可以引发明确定义的一维相变。通过原位像差校正透射电子显微镜检查石墨烯之字形边缘结构重建的动力学。结合从头算模拟和量子化学分子动力学的深入分析，在原子尺度上清楚地展示和理解了石墨烯之字形边缘处的完整缺陷诱导的一维相变动力学。此外，按照这种相变方案，可以制造具有不同边缘对称性的石墨烯纳米带（GNR），并且根据我们的电子结构和量子输运计算，提出了超薄GNR的金属-绝缘体-半导体转变。
One well-known argument about a one-dimensional (1D) system is that 1D phase transition at finite temperature cannot exist even though this concept depends on conditions such as range of interaction, external fields, and periodicity. Therefore, 1D systems usually have random fluctuations with intrinsic domain walls arising that naturally bring disorder during transition. Herein, we introduce a real 1D system in which artificially created defects can induce a well-defined ID phase transition. The dynamics of structural reconstructions at graphene zigzag edges are examined by in situ aberration-corrected transmission electron microscopy. Combined with an in-depth analysis by ab initio simulations and quantum chemical molecular dynamics, the complete defect induced 1D phase transition dynamics at graphene zigzag edge is clearly demonstrated and understood on the atomic scale. Further, following this phase transition scheme, graphene nanoribbons (GNR) with different edge symmetries can be fabricated and, according to our electronic structure and quantum transport calculations, a metal-insulator-semiconductor transition for ultrathin GNRs is proposed.