title: Density dependent exchange contribution to partial differential mu/ partial differential n and compressibility in graphene.
abstract: We calculate partial differentialmu/ partial differentialn (where mu=chemical potential and n=electron density), which is associated with the compressibility, in graphene as a function of n, within the Hartree-Fock approximation. The exchange-driven Dirac-point logarithmic singularity in the quasiparticle velocity of intrinsic graphene disappears in the extrinsic case. The calculated renormalized partial differentialmu/ partial differentialn in extrinsic graphene on SiO2 has the same n;{-(1/2)} density dependence but is 20% larger than the inverse bare density of states, a relatively weak effect compared to the corresponding parabolic-band case. We predict that the renormalization effect can be enhanced to about 50% by changing the graphene substrate.
authors.affiliation: Condensed Matter Theory Center, Department of Physics, University of Maryland, College Park, Maryland 20742-4111, USA.
authors.forename: E H
authors.initials: EH
authors.lastname: Hwang
authors.forename: Ben Yu-Kuang
authors.initials: BY
authors.lastname: Hu
authors.forename: S
authors.initials: S
authors.lastname: Das Sarma