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

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.