arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2006.00399cond-mat.mes-hall
收藏

Twisted Trilayer Graphene:一个精确调谐的关联电子平台

Twisted Trilayer Graphene: a Precisely Tunable Platform for Correlated Electrons

Ziyan Zhu, Stephen Carr, Daniel Massatt, Mitchell Luskin, Efthimios Kaxiras

摘要:

我们引入扭曲的三层石墨烯(tTLG)作为一个理想的系统,具有两个独立的扭曲角的电子层间耦合的精确调谐,以最大限度地提高相关行为的效果。如通过相关的扭曲双层石墨烯系统中的实验和理论所建立的,状态密度中的范霍夫奇点(VHS)可以用作相关行为的趋势的代理。为了探索扭曲角相空间中VHS的演化,我们提出了一个通用的低能电子结构模型的任意对扭曲角。我们表明,该模型的基础具有无限的尺寸,即使在一个有限的能量截止,并没有布里渊区存在,即使在连续极限。使用这个模型,我们证明了tTLG系统表现出很宽的幻角范围内的VHS合并和状态密度有一个尖锐的峰值在电荷中性点通过两个不同的机制:扭曲的双层石墨烯的平带的无公度扰动或两个双层莫尔超晶格之间的相等杂化。

英文摘要:

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.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑