Eom Daejin, Koo Ja-Yong
Korea Research Institute of Standards and Science, Yuseong, Daejeon 34113, Republic of Korea.
Nanoscale. 2020 Oct 14;12(38):19604-19608. doi: 10.1039/d0nr03565c. Epub 2020 Sep 30.
Kekulé distortion in graphene is a subject of extensive theoretical studies due to its non-trivial material properties. Yet, experimental observation of its formation mechanism and electronic structures is still elusive. Here, we used scanning tunneling microscopy to visualize two different phases of the Kekulé distortion in graphene along with experimental evidence that local strain is responsible for the formation of such distortions. In addition, we directly measured the electronic structures of the two phases of the Kekulé distortion in graphene revealing that one opens an energy gap whereas the other maintains a linear density profile. These are consistent with the calculated band structures of the two phases of the Kekulé distortion, respectively, providing a direct verification of the theoretical predictions.
由于其非平凡的材料特性，石墨烯中的凯库勒畸变是广泛理论研究的主题。然而，对其形成机制和电子结构的实验观测仍然难以捉摸。在这里，我们使用扫描隧道显微镜来可视化石墨烯中凯库勒畸变的两个不同相，并提供实验证据表明局部应变是这种畸变形成的原因。此外，我们直接测量了石墨烯中凯库勒畸变两个相的电子结构，发现其中一个打开了能隙，而另一个保持线性密度分布。这些分别与凯库勒畸变两个相的计算能带结构一致，为理论预测提供了直接验证。
