Compressibility of the electron gas in bilayer graphene

Bilayer graphene is a recently isolated and intriguing interacting electron system with massive chiral quasiparticles. We present theoretical results for the electronic compressibility of bilayer graphene that are based on a four-band continuum band structure model combined with a random phase approximation treatment of electronic correlations. We find that the compressibility is strongly suppressed by electron-electron interactions at low-carrier densities. Correlations do not lead to any qualitative new features but are crucially important for a quantitative understanding of this fundamental thermodynamic property of graphene bilayers.