• 文献标题:   Chemical potential and quantum Hall ferromagnetism in bilayer graphene
  • 文献类型:   Article
  • 作  者:   LEE K, FALLAHAZAD B, XUE JM, DILLEN DC, KIM K, TANIGUCHI T, WATANABE K, TUTUC E
  • 作者关键词:  
  • 出版物名称:   SCIENCE
  • ISSN:   0036-8075 EI 1095-9203
  • 通讯作者地址:   Univ Texas Austin
  • 被引频次:   70
  • DOI:   10.1126/science.1251003
  • 出版年:   2014

▎ 摘  要

Bilayer graphene has a distinctive electronic structure influenced by a complex interplay between various degrees of freedom. We probed its chemical potential using double bilayer graphene heterostructures, separated by a hexagonal boron nitride dielectric. The chemical potential has a nonlinear carrier density dependence and bears signatures of electron-electron interactions. The data allowed a direct measurement of the electric field-induced bandgap at zero magnetic field, the orbital Landau level (LL) energies, and the broken-symmetry quantum Hall state gaps at high magnetic fields. We observe spin-to-valley polarized transitions for all half-filled LLs, as well as emerging phases at filling factors v = 0 and v = +/- 2. Furthermore, the data reveal interaction-driven negative compressibility and electron-hole asymmetry in N = 0, 1 LLs.