• 文献标题:   Uncovering Topological Edge States in Twisted Bilayer Graphene
  • 文献类型:   Article
  • 作  者:   FORTINDESCHENES M, PU R, ZHOU YF, MA C, CHEUNG P, WATANABE K, TANIGUCHI T, ZHANG F, DU X, XIA FN
  • 作者关键词:   twodimensional material, twisted bilayer graphene, topology, edge state, josephson junction, moire
  • 出版物名称:   NANO LETTERS
  • ISSN:   1530-6984 EI 1530-6992
  • 通讯作者地址:  
  • 被引频次:   4
  • DOI:   10.1021/acs.nanolett.2c01481 EA JUL 2022
  • 出版年:   2022

▎ 摘  要

Twisted bilayer graphene (t-BLG) has recently been introduced as a rich physical platform displaying flat electronic bands, strongly correlated states, and unconventional superconductivity. Studies have hinted at an unusual Z(2) topology of the moire Dirac bands of t-BLG. However, direct experimental evidence of this moire band topology and associated edge states is still lacking. Herein, using superconducting quantum interferometry, we reconstructed the spatial supercurrent distribution in t-BLG Josephson junctions and revealed the presence of edge states located in the superlattice band gaps. The absence of edge conduction in high resistance regions just outside the superlattice band gap confirms that the edge transport originates from the filling of electronic states located inside the band gap and further allows us to exclude several other edge conduction mechanisms. These results confirm the unusual moire band topology of twisted bilayer graphene and will stimulate further research to explore its consequences.