Robust optical conductivity in gapped graphene

TL;DR

This paper investigates the optical conductivity in gapped graphene, revealing a scaling relation involving key parameters and establishing an exact ratio between bilayer and monolayer graphene conductivities.

Contribution

It introduces a scaling relation for optical conductivity in gapped graphene and derives an exact ratio between bilayer and monolayer graphene conductivities.

Findings

Optical conductivity follows a specific scaling relation with frequency, gap, Fermi energy, and temperature.

The ratio of optical conductivity between bilayer and monolayer graphene is exactly 2.

The scaling relation simplifies understanding of optical responses in gapped graphene.

Abstract

We study the optical conductivity in the low-energy regime of gapped mono- and bilayer graphene. A scaling relation is found, in which the four parameters frequency, gap, Fermi energy and temperature appear only as combination of three independent parameters. The ratio of the optical conductivity of bilayer and mononlayer graphene is exactly 2.