Flat bands in slightly twisted bilayer graphene: Tight-binding calculations
Flat bands in slightly twisted bilayer graphene: Tight-binding calculations
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DOI：
10.1103/physrevb.82.121407
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发表时间：
2010-09-13
影响因子：
3.7
通讯作者：
Barticevic, Z.
中科院分区：
文献类型：
--
作者：
Suarez Morell, E.;Correa, J. D.;Barticevic, Z.
费米能级附近平带的存在被认为是高转变温度超导体的一种解释。石墨的能带对改变电子结构的拓扑缺陷极为敏感。在这次快速通信中，我们发现在轻微扭曲的双层石墨烯中，费米能量不超过10 meV的非色散平坦带是从双层石墨烯的抛物线色散向石墨烯的特征线性色散转变的标志。这种转变发生在层的相对旋转角大约1.5度时，并且与层分离的过程有关。我们进行了从头计算，建立了一个具有层间相互作用哈密顿量的紧束缚模型，该模型包括所有原子的pi轨道，并考虑了层内直到第三近邻的相互作用。
The presence of flat bands near Fermi level has been proposed as an explanation for high transition temperature superconductors. The bands of graphite are extremely sensitive to topological defects which modify the electronic structure. In this Rapid Communication, we found nondispersive flat bands no farther than 10 meV of the Fermi energy in slightly twisted bilayer graphene as a signature of a transition from a parabolic dispersion of bilayer graphene to the characteristic linear dispersion of graphene. This transition occurs for relative rotation angles of layers around 1.5 degrees and is related to a process of layer decoupling. We have performed ab initio calculations to develop a tight-binding model with an interaction Hamiltonian between layers that include the pi orbitals of all atoms and takes into account interactions up to third nearest neighbors within a layer.