Energy Gaps at Neutrality Point in Bilayer Graphene in a Magnetic Field

Utilizing the Baym-Kadanoff formalism with the polarization function calculated in the random phase approximation, the dynamics of the nu=0 quantum Hall state in bilayer graphene is analyzed. Two phases with nonzero energy gap, the ferromagnetic and layer asymmetric ones, are found. The phase diagram in the plane ((Delta) over tilde (0), B), where (Delta) over tilde (0) is a top-bottom gates voltage imbalance, is described. It is shown that the energy gap scales linearly, Delta E similar to 14B [T] K, with magnetic field.