论文标题
扭曲的三层石墨烯：相关电子的精确调谐平台
Twisted Trilayer Graphene: a Precisely Tunable Platform for Correlated Electrons
论文作者
论文摘要
我们引入了具有两个独立扭曲角度的扭曲三层石墨烯（TTLG），作为对电子层层耦合进行精确调整的理想系统，以最大程度地提高相关行为的效果。正如实验和理论在相关扭曲的双层石墨烯系统中确定的那样，状态密度中的Van Hove奇异性（VHS）可以用作相关行为趋势的代表。为了探索在TTLG的扭角空间中VHS的演变，我们为任何一对扭曲角度提供了一般的低能电子结构模型。我们表明，该模型的基础即使在有限的能量截止下也具有无限的尺寸，即使在连续限制中，也没有布里鲁因区域。使用该模型，我们证明了TTLG系统表现出各种魔法角度，VHS合并和状态的密度通过两种不同的机制在电荷中性点上具有尖锐的峰值：扭曲的双层石墨烯的平面带或两个Bielbridization twisted Billayer flateriation twistrate the Intripation toction-neutrality Point：不予以强度的扰动。
We introduce twisted trilayer graphene (tTLG) with two independent twist angles as an ideal system for the precise tuning of the electronic interlayer coupling to maximize the effect of correlated behaviors. As established by experiment and theory in the related twisted bilayer graphene system, van Hove singularities (VHS) in the density of states can be used as a proxy of the tendency for correlated behaviors. To explore the evolution of VHS in the twist-angle phase space of tTLG, we present a general low-energy electronic structure model for any pair of twist angles. We show that the basis of the model has infinite dimensions even at a finite energy cutoff and that no Brillouin zone exists even in the continuum limit. Using this model, we demonstrate that the tTLG system exhibits a wide range of magic angles at which VHS merge and the density of states has a sharp peak at the charge-neutrality point through two distinct mechanisms: the incommensurate perturbation of twisted bilayer graphene's flat bands or the equal hybridization between two bilayer moiré superlattices.
