Optical conductivity and transparency in an effective model for graphene

Abstract

Motivated by experiments confirming that the optical transparency of graphene is defined through the fine structure constant and that it could be fully explained within the relativistic Dirac fermions in a two-dimensional picture, we investigate in this article how this property is affected by next-to-nearest-neighbor coupling in the low-energy continuum description of graphene. A detailed calculation within the linear response regime allows us to conclude that, somewhat surprisingly, the optical conductivity at zero temperature that determines the transparency remains robust up to this correction.