Excitonic gap formation and condensation in the bilayer graphene structure

TL;DR

This paper investigates how excitonic gaps form and condense in bilayer graphene, analyzing Coulomb interactions, interlayer hopping, and temperature effects to understand phase transitions and optical properties.

Contribution

It provides a detailed theoretical analysis of excitonic gap formation and condensation in bilayer graphene considering Coulomb interactions and interlayer effects.

Findings

Excitonic gap formation is influenced by interlayer Coulomb interactions.

Temperature affects the size and stability of the excitonic gap.

Different interlayer correlation regimes are characterized in the phase diagram.

Abstract

We have studied the excitonic gap formation in the Bernal Stacked, bilayer graphene (BLG) structures at half-filling. Considering the local Coulomb interaction between the layers, we calculate the excitonic gap parameter and we discuss the role of the interlayer and intralayer Coulomb interactions and the interlayer hopping on the excitonic pair formation in the BLG. Particularly, we predict the origin of excitonic gap formation and condensation, in relation to the farthermost interband optical transition spectrum. The general diagram of excitonic phase transition is given, explaining different interlayer correlation regimes. The temperature dependence of the excitonic gap parameter is shown and the role of the chemical potential, in the BLG, is discussed in details.