• 文献标题:   Electronic Compressibility of Magic-Angle Graphene Superlattices
  • 文献类型:   Article
  • 作  者:   TOMARKEN SL, CAO Y, DEMIR A, WATANABE K, TANIGUCHI T, JARILLOHERRERO P, ASHOORI RC
  • 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:   MIT
  • 被引频次:   28
  • DOI:   10.1103/PhysRevLett.123.046601
  • 出版年:   2019

▎ 摘  要

We report the first electronic compressibility measurements of magic-angle twisted bilayer graphene. The evolution of the compressibility with carrier density offers insights into the interaction-driven ground state that have not been accessible in prior transport and tunneling studies. From capacitance measurements, we determine the chemical potential as a function of carrier density and find the widths of the energy gaps at fractional filling of the moire lattice. In the electron-doped regime, we observe unexpectedly large gaps at quarter- and half-filling and strong electron-hole asymmetry. Moreover, we measure a similar to 35 meV minibandwidth that is much wider than most theoretical estimates. Finally, we explore the field dependence up to the quantum Hall regime and observe significant differences from transport measurements.