Effective Dirac Hamiltonian for anisotropic honeycomb lattices: optical properties

TL;DR

This paper derives an effective Dirac Hamiltonian for anisotropic honeycomb lattices, analyzing their optical conductivity, transmittance, and dichroic properties, with applications to strained graphene.

Contribution

It provides a generalized low-energy Hamiltonian for anisotropic honeycomb lattices and explores their optical properties, extending previous models to include nonmechanical distortions.

Findings

Derived the optical conductivity tensor for anisotropic honeycomb lattices.

Characterized the dichroic optical absorption due to anisotropy.

Applied the model to study optical properties of strained graphene.

Abstract

We derive the low-energy Hamiltonian for a honeycomb lattice with anisotropy in the hopping parameters. Taking the reported Dirac Hamiltonian for the anisotropic honeycomb lattice, we obtain its optical conductivity tensor and its transmittance for normal incidence of linearly polarized light. Also, we characterize its dichroic character due to the anisotropic optical absorption. As an application of our general findings, which reproduce the case of uniformly strained graphene, we study the optical properties of graphene under a nonmechanical distortion.