  The unique capabilities of capacitance measurements in bilayer graphene
enable probing of layer-specific properties that are normally out of reach in
transport measurements. Furthermore, capacitance measurements in the top-gate
and penetration field geometries are sensitive to different physical
quantities: the penetration field capacitance probes the two layers equally,
whereas the top gate capacitance preferentially samples the near layer,
resulting in the "near-layer capacitance enhancement" effect observed in recent
top-gate capacitance measurements. We present a detailed theoretical
description of this effect and show that capacitance can be used to determine
the equilibrium layer polarization, a potentially useful tool in the study of
broken symmetry states in graphene.
