论文标题
低角度扭曲的双层石墨烯
Tunable Sample-wide Electronic Kagome Lattice in Low-angle Twisted Bilayer Graphene
论文作者
论文摘要
将两个具有小扭曲角的石墨烯层覆盖可以产生一个Moire超晶格，以实现石墨烯单层中完全不存在的外来现象。一个代表性的例子是，当将石墨烯层受到不同的静电电位时，在微角扭曲的双层石墨烯（TBG）中，具有kagome twist的双层石墨烯（TBG）的局部伪landau水平（PLL）的预测形成。 However, this was shown only for the model of rigidly rotated TBG which is not realized in reality due to an interfacial structural reconstruction.据认为，界面结构重建强烈抑制了PLL的形成。在这里，我们系统地研究了TBG的电子特性，其电子性质为0.075度<theta <1.2 ver，并出乎意料地证明了PLL对于所有研究的TBG都非常强大。结构重建抑制了小角度TBG中新出现的Kagome晶格的形成。但是，对于围绕魔术角的TBG，通过使用扫描隧道显微镜直接成像具有可调晶格常数的整个样品电子kagome晶格。我们的观察结果为探索Moire Systems中的异国相关阶段打开了一个新的方向。
Overlaying two graphene layers with a small twist angle can create a moire superlattice to realize exotic phenomena that are entirely absent in graphene monolayer. A representative example is the predicted formation of localized pseudo-Landau levels (PLLs) with Kagome lattice in tiny-angle twisted bilayer graphene (TBG) with theta < 0.3 deg when the graphene layers are subjected to different electrostatic potentials. However, this was shown only for the model of rigidly rotated TBG which is not realized in reality due to an interfacial structural reconstruction. It is believed that the interfacial structural reconstruction strongly inhibits the formation of the PLLs. Here, we systematically study electronic properties of the TBG with 0.075 deg < theta < 1.2 deg and demonstrate, unexpectedly, that the PLLs are quite robust for all the studied TBG. The structural reconstruction suppresses the formation of the emergent Kagome lattice in the tiny-angle TBG. However, for the TBG around magic angle, the sample-wide electronic Kagome lattices with tunable lattice constants are directly imaged by using scanning tunneling microscope. Our observations open a new direction to explore exotic correlated phases in moire systems.
