Exciton formation in graphene bilayer
arXiv:0709.1230 · doi:10.1103/PhysRevB.78.045401
Abstract
Exciton instability in graphene bilayer systems is studied in the case of a short-ranged Coulomb interaction and a finite voltage difference between the layers. Self-consistent exciton gap equations are derived and solved numerically and analytically under controlled approximation. We obtain that a critical strength of the Coulomb interaction exists for the formation of excitons. The critical strength depends on the amount of voltage difference between the layers and on the inter-layer hopping parameter.
10 pages, 11 figures