• 文献标题:   Emergent ferromagnetism near three-quarters filling in twisted bilayer graphene
  • 文献类型:   Article
  • 作  者:   SHARPE AL, FOX EJ, BARNARD AW, FINNEY J, WATANABE K, TANIGUCHI T, KASTNER MA, GOLDHABERGORDON D
  • 作者关键词:  
  • 出版物名称:   SCIENCE
  • ISSN:   0036-8075 EI 1095-9203
  • 通讯作者地址:   SLAC Natl Accelerator Lab
  • 被引频次:   186
  • DOI:   10.1126/science.aaw3780
  • 出版年:   2019

▎ 摘  要

When two sheets of graphene are stacked at a small twist angle, the resulting flat superlattice minibands are expected to strongly enhance electron-electron interactions. Here, we present evidence that near three-quarters (3/4) filling of the conduction miniband, these enhanced interactions drive the twisted bilayer graphene into a ferromagnetic state. In a narrow density range around an apparent insulating state at 3/4, we observe emergent ferromagnetic hysteresis, with a giant anomalous Hall (AH) effect as large as 10.4 kilohms and indications of chiral edge states. Notably, the magnetization of the sample can be reversed by applying a small direct current. Although the AH resistance is not quantized, and dissipation is present, our measurements suggest that the system may be an incipient Chern insulator.