扭曲双层石墨烯中的异常磁输运
Unusual magnetotransport in twisted bilayer graphene.
作者信息
Finney Joe, Sharpe Aaron L, Fox Eli J, Hsueh Connie L, Parker Daniel E, Yankowitz Matthew, Chen Shaowen, Watanabe Kenji, Taniguchi Takashi, Dean Cory R, Vishwanath Ashvin, Kastner M A, Goldhaber-Gordon David
机构信息
Department of Physics, Stanford University, Stanford, CA 94305.
Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA 94025.
出版信息
Proc Natl Acad Sci U S A. 2022 Apr 19;119(16):e2118482119. doi: 10.1073/pnas.2118482119. Epub 2022 Apr 11.
SignificanceWhen two sheets of graphene are twisted to the magic angle of 1.1, the resulting flat moiré bands can host exotic correlated electronic states such as superconductivity and ferromagnetism. Here, we show transport properties of a twisted bilayer graphene device at 1.38, far enough above the magic angle that we do not expect exotic correlated states. Instead, we see several unusual behaviors in the device's resistivity upon tuning both charge carrier density and perpendicular magnetic field. We can reproduce these behaviors with a surprisingly simple model based on Hofstadter's butterfly. These results shed light on the underlying properties of twisted bilayer graphene.
意义
当两层石墨烯被扭曲到1.1的神奇角度时，由此产生的平坦莫尔带可以容纳奇异的相关电子态，如超导和铁磁性。在这里，我们展示了一个扭曲双层石墨烯器件在1.38时的输运特性，该角度远高于神奇角度，因此我们预计不会出现奇异的相关态。相反，在调节载流子密度和垂直磁场时，我们在器件的电阻率中看到了几种不寻常的行为。我们可以用一个基于霍夫施塔特蝴蝶的惊人简单模型来重现这些行为。这些结果揭示了扭曲双层石墨烯的潜在特性。
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