Determination of the electronic structure of bilayer graphene from infrared spectroscopy results

TL;DR

This study combines experimental infrared spectroscopy with theoretical modeling to analyze the electronic structure of bilayer graphene, revealing how interlayer interactions influence its optical properties and parameter values.

Contribution

It provides a detailed experimental and theoretical analysis of bilayer graphene's electronic structure using the SWMc model and infrared spectroscopy.

Findings

The main conductivity peak position is determined by interlayer tunneling.

Gate voltage shifts reveal parameters related to electron-hole and sublattice asymmetries.

Results align with recent electronic structure calculations.

Abstract

We present an experimental study of the infrared conductivity, transmission, and reflection of a gated bilayer graphene and their theoretical analysis within the Slonczewski-Weiss-McClure (SWMc) model. The infrared response is shown to be governed by the interplay of the interband and the intraband transitions among the four bands of the bilayer. The position of the main conductivity peak at the charge neutrality point is determined by the interlayer tunneling frequency. The shift of this peak as a function of the gate voltage gives information about less known parameters of the SWMc model, in particular, those responsible for the electron-hole and sublattice asymmetries. These parameter values are shown to be consistent with recent electronic structure calculations for the bilayer graphene and the SWMc parameters commonly used for the bulk graphite.