论文标题
扭曲的双层石墨烯中的分数Chern绝缘子和电荷密度波相的相互作用
Interplay of Fractional Chern Insulator and Charge-Density-Wave Phases in Twisted Bilayer Graphene
论文作者
论文摘要
我们对扭曲的双层石墨烯的自旋和山谷偏振的摩尔型扁平带进行了相互作用驱动的绝缘体的广泛的对角研究，并与其六角形氮化硼一排成一致。除了先前报道的分数Chern绝缘子阶段外，我们还为在逼真的单波段模型的多个分数填充物处提供了令人信服的证据。在不同的层中跳跃参数上进行了彻底的分析，这是由实验变异性动机，动能在各种库仑相互作用强度上的作用突出了这些阶段之间的竞争。单粒子的相互作用以及相互作用引起的孔分散与Chern带的固有浆果曲率的相互作用，被直观地理解为用于基础选择的驱动机制。所得的相图具有与相关的Moiré异质结构中实验发现的显着一致性，并确认了我们的结果的相关性，而不是基于石墨烯的材料的范围。
We perform an extensive exact diagonalization study of interaction driven insulators in spin- and valley-polarized moiré flat bands of twisted bilayer graphene aligned with its hexagonal boron nitride substrate. In addition to previously reported fractional Chern insulator phases, we provide compelling evidence for competing charge-density-wave phases at multiple fractional fillings of a realistic single-band model. A thorough analysis at different interlayer hopping parameters, motivated by experimental variability, and the role of kinetic energy at various Coulomb interaction strengths highlight the competition between these phases. The interplay of the single-particle and the interaction induced hole dispersion with the inherent Berry curvature of the Chern bands is intuitively understood to be the driving mechanism for the ground-state selection. The resulting phase diagram features remarkable agreement with experimental findings in a related moiré heterostructure and affirms the relevance of our results beyond the scope of graphene based materials.
