Quantum field theoretical description for the reflectivity of graphene

TL;DR

This paper develops a quantum field theoretical model to accurately describe the reflectivity of graphene across frequencies, incorporating temperature effects and providing analytic and numerical results for reflection coefficients.

Contribution

It introduces a new analytic continuation of the polarization tensor for graphene, enabling a more precise quantum field theoretical description of its optical reflectivity.

Findings

Derived analytic asymptotic expressions for reflection coefficients.

Numerically validated the applicability of asymptotic formulas.

Explored frequency and angle dependencies of graphene's reflectivity.

Abstract

We derive the polarization tensor of graphene at nonzero temperature in (2+1)-dimensional space-time. The obtained tensor coincides with the previously known one at all Matsubara frequencies, but, in contrast to it, admits analytic continuation to the real frequency axis satisfying all physical requirements. Using the obtained representation for the polarization tensor, we develope quantum field theoretical description for the reflectivity of graphene. The analytic asymptotic expressions for the reflection coefficients and reflectivities at low and high frequencies are derived for both independent polarizations of the electromagnetic field. The dependencies of reflectivities on the frequency and angle of incidence are investigated. Numerical computations using the exact expressions for the polarization tensor are performed and application regions for the analytic asymptotic results are determined.