title: Space charge and screening in bilayer graphene.
abstract: Undoped bilayer graphene is a two-dimensional semimetal with a low-energy excitation spectrum that is parabolic in the momentum. As a result, the screening of an arbitrary external charge Ze is accompanied by a reconstruction of the ground state: valence band electrons (for Z  >  0) are promoted to form a space charge around the charge while the holes leave the physical picture. The outcome is a flat neutral object resembling the regular atom except that for [Formula: see text] it is described by a strictly linear Thomas-Fermi theory. This theory also predicts that the bilayer's static dielectric constant is the same as that of a two-dimensional electron gas in the long-wavelength limit.
authors.affiliation: Department of Physics, University of Virginia, PO Box 400714, Charlottesville, VA 22904-4714, USA.
authors.forename: Eugene B
authors.initials: EB
authors.lastname: Kolomeisky
authors.forename: Joseph P
authors.initials: JP
authors.lastname: Straley
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Abrams