Effective mass of electrons and holes in bilayer graphene: Electron-hole asymmetry and electron-electron interaction

Authors

K. Zou, The Pennsylvania State University
X. Hong, University of Nebraska–LincolnFollow
J. Zhu, The Pennsylvania State UniversityFollow

Document Type

Article

Date of this Version

2011

Citation

PHYSICAL REVIEW B 84, 085408 (2011); DOI: 10.1103/PhysRevB.84.085408

Comments

Copyright 2011 American Physical Society. Used by permission.

Abstract

Precision measurements of the effective mass m^* in high-quality bilayer graphene using the temperature dependence of the Shubnikov–de Haas oscillations are reported. In the density range 0.7 × 1012 < n < 4.1 × 10¹² cm⁻², both the hole mass m^*_h and the electron mass m^*_e increase with increasing density, demonstrating the hyperbolic nature of the bands. The hole mass m^*_h is approximately 20–30% larger than the electron mass m^*_e . Tight-binding calculations provide a good description of the electron-hole asymmetry and yield an accurate measure of the interlayer hopping parameter v₄ = 0.063. Both m^*_h and m^*_e are suppressed compared with single particle values, suggesting renormalization of the band structure of bilayer graphene induced by electron-electron interaction.