• 文献标题:   Compressibility of graphene
  • 文献类型:   Article
  • 作  者:   ABERGEL DSL, HWANG EH, DAS SARMA S
  • 作者关键词:  
  • 出版物名称:   PHYSICAL REVIEW B
  • ISSN:   1098-0121
  • 通讯作者地址:   Univ Maryland
  • 被引频次:   18
  • DOI:   10.1103/PhysRevB.83.085429
  • 出版年:   2011

▎ 摘  要

We develop a theory for the compressibility and quantum capacitance of disordered monolayer and bilayer graphene, including the full hyperbolic band structure and band gap in the latter case. We include the effects of disorder in our theory, which are of particular importance at the carrier densities near the Dirac point. We account for this disorder statistically using two different averaging procedures: first via averaging over the density of carriers directly, and then via averaging in the density of states to produce an effective density of carriers. We also compare the results of these two models with experimental data, and to do this we introduce a model for interlayer screening which predicts the size of the band gap between the low-energy conduction and valence bands for arbitrary gate potentials applied to both layers of bilayer graphene. We find that both models for disorder give qualitatively correct results for gapless systems, but when there is a band gap in the low-energy band structure, the density of states averaging is incorrect and disagrees with the experimental data.