Department of Physics, Beijing Normal University, Beijing 100875, China.
Nat Commun. 2013;4:2159. doi: 10.1038/ncomms3159.
It is well established that strain and geometry could affect the band structure of graphene monolayer dramatically. Here we study the evolution of local electronic properties of a twisted graphene bilayer induced by a strain and a high curvature, which are found to strongly affect the local band structures of the twisted graphene bilayer. The energy difference of the two low-energy van Hove singularities decreases with increasing lattice deformation and the states condensed into well-defined pseudo-Landau levels, which mimic the quantization of massive chiral fermions in a magnetic field of about 100 T, along a graphene wrinkle. The joint effect of strain and out-of-plane distortion in the graphene wrinkle also results in a valley polarization with a significant gap. These results suggest that strained graphene bilayer could be an ideal platform to realize the high-temperature zero-field quantum valley Hall effect.
已有研究证实，应变和几何形状会显著影响单层石墨烯的能带结构。在这里，我们研究了应变和高曲率引起的扭曲双层石墨烯局部电子性质的演变，发现它们强烈影响扭曲双层石墨烯的局部能带结构。两个低能范霍夫奇点的能量差随晶格变形的增加而减小，状态凝聚成明确定义的赝 Landau 能级，这模拟了在约 100 T 的磁场中，沿着石墨烯褶皱的大量手性费米子的量子化。应变和石墨烯褶皱中面外变形的共同作用也导致具有显著能隙的谷极化。这些结果表明，应变双层石墨烯可能是实现高温零场量子谷霍尔效应的理想平台。
