Band structure asymmetry of bilayer graphene revealed by infrared spectroscopy

TL;DR

This study uses infrared spectroscopy to reveal a significant asymmetry in the optical conductivity of bilayer graphene caused by sublattice inequivalence, providing insights into its electronic band structure.

Contribution

It demonstrates the asymmetry in bilayer graphene's optical properties and quantifies the energy difference between sublattices using spectroscopy data.

Findings

Asymmetry in optical conductivity between electrons and holes

Quantification of sublattice energy difference

Evidence of valence and conduction band asymmetry

Abstract

We report on infrared spectroscopy of bilayer graphene integrated in gated structures. We observed a significant asymmetry in the optical conductivity upon electrostatic doping of electrons and holes. We show that this finding arises from a marked asymmetry between the valence and conduction bands, which is mainly due to the inequivalence of the two sublattices within the graphene layer. From the conductivity data, the energy difference of the two sublattices is determined.