Light absorption in distorted graphene

Abstract

We model the low energy dynamics of graphene in the continuum in terms of a version of reduced quantum electrodynamics (QED) restricting fermions to a [Formula: see text]-dimensional brane, while photons remain within the [Formula: see text]-dimensional bulk. For charge carriers, besides the Dirac mass gap, we consider a Haldane mass term which is induced by parametrizing an effective parity [Formula: see text] and time-reversal [Formula: see text] symmetry breaking that occurs on the brane when distortions of the honeycomb array are such that the equivalence between sublattices is lost. We make use of the relativistic Kubo formula and carry out an explicit calculation of the transverse conductivity. As expected, the filling factor is a half (in natural units) for each fermion species. Furthermore, assuming that a sample of this material is radiated perpendicularly with polarized monochromatic light of frequency [Formula: see text], from the modified Maxwell’s equations we address the problem of light absorption in graphene in terms of the said conductivity. We observe that light penetrating the sample changes its angle of polarization solely by effect of the induced mass, in analogy to the Faraday effect but in absence of magnetic fields. This effect might be relevant for the development of optic filters based on mechanical stretching of graphene flakes.