Investigating the Longitudinal Optical Conductivity in Three-Layer Graphene Systems with Composes Mono-Bi-Bi and Bi-Mono-Bi and Bi-Bi-Mono

Document Type : Research Paper

Abstract

The longitudinal optical conductivity is the most important property for graphene-based
devices. So investigating this property for spatially separated few-layer graphene systems analytically
and numerically is the main purpose of our study. Each layer can be mono- or bi-layer graphene. The
density-density correlation function has been screened by the dielectric function using the random
phase approximation, which includes the inter-layer Coulomb coupling. By using Kronecker delta and
dielectric tensors, the optical conductivity, is calculated, and plotted as a function of photon energy
for three-layer graphene systems with composes mono-bi-bi, bi-mono-bi, and bi-bi-mono in different
broadening widths. In the presence of the potential function between the layers, the carrier densities in
each layer can be tuned respectively. In these two dimensional layered structures; the main contributions
to the optical conductivity are from the intra- and inter-band transition channels in a same layer.

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