DISPERSION RELATIONS IN BILAYER GRAPHENE AT FINITE TEMPERATURE

Abstract

It is well-known that material technology is considered as one of the scientific fields attracting a lot of attention from scientists. Recently, graphene, a perfect two-dimensional structure, has attracted a large amount of interest from researchers due to its unique properties and possible applications in a variety of technological fields. The dispersion relations in graphene demonstrate that this material can be used to create plasmonic devices with potentially more features and less energy consumption than recent semiconductors. This paper calculates the dispersion relations in a bilayer graphene structure at finite temperatures using the random-phase approximation. The numerical results show that as temperature increases from zero, the plasmon frequency decreases slightly near the Dirac points and then increases noticeably. In large wave vector regions, the plasmon frequency behaves as an increasing function of temperature. The contribution of carrier density to plasmon frequency in the bilayer graphene system diminishes when temperature effects are taken into account. We observed that temperature significantly affects the dispersion relations in bilayer graphene systems; therefore, this factor should not be neglected in efforts to improve models or in comparisons with experimental results.

Keywords

• bilayer graphene
• dispersion relations
• dynamical dielectric function
• finite temperature
• random-phase approximation.