• 文献标题:   Quasi-flat-band physics in a two-leg ladder model and its relation to magic-angle twisted bilayer graphene
  • 文献类型:   Article
  • 作  者:   HUANG YX, HOSUR P, PAL HK
  • 作者关键词:  
  • 出版物名称:   PHYSICAL REVIEW B
  • ISSN:   2469-9950 EI 2469-9969
  • 通讯作者地址:   Indian Inst Technol
  • 被引频次:   0
  • DOI:   10.1103/PhysRevB.102.155429
  • 出版年:   2020

▎ 摘  要

We study the single- and many-particle properties of a two-leg ladder model threaded by a flux with the legs coupled by a spatially varying term. Although a priori unrelated to twisted bilayer graphene (TBG), the model is found to have striking similarities: a quasi-flat low-energy band emerges with characteristics similar to that of magic angle TBG. We study the effect of interparticle interaction in our model using the density matrix renormalization group and find that when the band is quasi-flat, the ground state is a ferromagnetic Mott insulator. As the band becomes more dispersive, the system undergoes a ferromagnetic to antiferromagnetic transition. We discuss how our model is relevant not only to magic-angle physics in TBG, but also in the larger context of one-dimensional correlations and magnetism.