Evidence for Interlayer Coupling and Moire Periodic Potentials in Twisted Bilayer Graphene
Evidence for Interlayer Coupling and Moire Periodic Potentials in Twisted Bilayer Graphene
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DOI：
10.1103/physrevlett.109.186807
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发表时间：
2012-11-02
影响因子：
8.6
通讯作者：
Beechem, Thomas E.
中科院分区：
文献类型：
--
作者：
Ohta, Taisuke;Robinson, Jeremy T.;Beechem, Thomas E.
我们利用角分辨光电子能谱和从头算方法研究了扭曲双层石墨烯的价带色散。我们观察到两个非相互作用的锥附近的狄拉克交叉能量和出现的货车霍韦奇性的锥重叠大扭转角（> 5度）。除了预期的狄拉克锥之间的相互作用，微型间隙出现在由两个石墨烯层的取向差形成的莫尔超晶格的布里渊区边界处。我们属性的出现，这些minigaps到一个周期性的潜力所引起的莫尔。这些反交叉特征指向两个石墨烯片之间的耦合，由莫尔周期势介导。
We report a study of the valence band dispersion of twisted bilayer graphene using angle-resolved photoemission spectroscopy and ab initio calculations. We observe two noninteracting cones near the Dirac crossing energy and the emergence of van Hove singularities where the cones overlap for large twist angles (> 5 degrees). Besides the expected interaction between the Dirac cones, minigaps appeared at the Brillouin zone boundaries of the moire superlattice formed by the misorientation of the two graphene layers. We attribute the emergence of these minigaps to a periodic potential induced by the moire. These anticrossing features point to coupling between the two graphene sheets, mediated by moire periodic potentials.