• 文献标题:   Correlated insulating and superconducting states in twisted bilayer graphene below the magic angle
  • 文献类型:   Article
  • 作  者:   CODECIDO E, WANG QY, KOESTER R, CHE S, TIAN HD, LV R, TRAN S, WATANABE K, TANIGUCHI T, ZHANG F, BOCKRATH M, LAU CN
  • 作者关键词:  
  • 出版物名称:   SCIENCE ADVANCES
  • ISSN:   2375-2548
  • 通讯作者地址:   Ohio State Univ
  • 被引频次:   32
  • DOI:   10.1126/sciadv.aaw9770
  • 出版年:   2019

▎ 摘  要

The emergence of flat bands and correlated behaviors in "magic angle" twisted bilayer graphene (tBLG) has sparked tremendous interest, though its many aspects are under intense debate. Here we report observation of both superconductivity and the Mott-like insulating state in a tBLG device with a twist angle of similar to 0.93 degrees, which is smaller than the magic angle by 15%. At an electron concentration of +/- 5 electrons/moire unit cell, we observe a narrow resistance peak with an activation energy gap similar to 0.1 meV. This indicates additional correlated insulating state, and is consistent with theory predicting a high-energy flat band. At doping of +/- 12 electrons/moire unit cell we observe resistance peaks arising from the Dirac points in the spectrum. Our results reveal that the "magic" range of tBLG is in fact larger than what is previously expected, and provide a wealth of new information to help decipher the strongly correlated phenomena observed in tBLG.