• 文献标题:   Spectroscopy of Twisted Bilayer Graphene Correlated Insulators
  • 文献类型:   Article
  • 作  者:   CALUGARU D, REGNAULT N, OH M, NUCKOLLS KP, WONG DL, LEE RL, YAZDANI A, VAFEK O, BERNEVIG BA
  • 作者关键词:  
  • 出版物名称:   PHYSICAL REVIEW LETTERS
  • ISSN:   0031-9007 EI 1079-7114
  • 通讯作者地址:  
  • 被引频次:   6
  • DOI:   10.1103/PhysRevLett.129.117602
  • 出版年:   2022

▎ 摘  要

We analytically compute the scanning tunneling microscopy (STM) signatures of integer-filled correlated ground states of the magic angle twisted bilayer graphene (TBG) narrow bands. After experimentally validating the strong-coupling approach at +/- 4 electrons/moire unit cell, we consider the spatial features of the STM signal for 14 different many-body correlated states and assess the possibility of Kekule distortion (KD) emerging at the graphene lattice scale. Remarkably, we find that coupling the two opposite graphene valleys in the intervalley-coherent (IVC) TBG insulators does not always result in KD. As an example, we show that the Kramers IVC state and its nonchiral U(4) rotations do not exhibit any KD, while the time-reversal-symmetric IVC state does. Our results, obtained over a large range of energies and model parameters, show that the STM signal and Chern number of a state can be used to uniquely determine the nature of the TBG ground state.