论文标题
Landau级别作为对石墨烯Moiré超级晶格中带拓扑的探测
Landau Levels as a Probe for Band Topology in Graphene Moiré Superlattices
论文作者
论文摘要
我们建议在二维Moiré超级晶格中对电子带的拓扑特征进行探测。我们考虑具有非常相似的带结构的扭曲双重双层石墨烯（TDBG）的两种配置，但显示了不同的平面频带的山谷数量。 TDBG的AB-AB和AB-BA构型之间的这些差异显然表现为使用紧密结合模型计算的Hofstadter Butterfly Spectra中不同的Landau级序列。从旋转$ C_2 $和时间反转$ \ MATHCAL {T} $ symmetries控制的动量空间中轨道磁化的分布的角度来解释了Landau级别的序列。我们的结果很容易扩展到其他扭曲的石墨烯多层和$ h $ bn/石墨烯异质结构，从而建立了Hofstadter Butterfly Spectra作为检测非平凡山谷带拓扑的强大工具。
We propose Landau levels as a probe for the topological character of electronic bands in two-dimensional moiré superlattices. We consider two configurations of twisted double bilayer graphene (TDBG) that have very similar band structures, but show different valley Chern numbers of the flat bands. These differences between the AB-AB and AB-BA configurations of TDBG clearly manifest as different Landau level sequences in the Hofstadter butterfly spectra calculated using the tight-binding model. The Landau level sequences are explained from the point of view of the distribution of orbital magnetization in momentum space that is governed by the rotational $C_2$ and time-reversal $\mathcal{T}$ symmetries. Our results can be readily extended to other twisted graphene multilayers and $h$-BN/graphene heterostructures thus establishing the Hofstadter butterfly spectra as a powerful tool for detecting the non-trivial valley band topology.
