Laboratoire de Physique Théorique
Toulouse - UMR 5152

Graphene, layers of two-dimensional honeycomb-array of carbon atoms, has attracted much interest these last few years due to its recent experimental accessibility and a wide variety of interesting properties. As the engineering application of the graphene layers attracts increasing significance, we need to explore, experimentally and theoretically, ways to enrich graphene’s electrical properties and to control them. One way to achieve some control over the electrical properties is to change the number of layers and/or the bias applied across the layers.

The bias can also potentially control the formation of excitons. Since the applied bias leads to the charge imbalance in the two layers, it is natural to suspect that the Coulomb attraction of the excess electrons and holes on opposite layers would lead to an exciton instability

In this seminar we consider the possibility of an excitonic instability in the biased graphene bilayer in the framework of Hartree-Fock theory.

see : Exciton formation in graphene bilayer, cond-mat/0709.1230.