Layer antiferromagnetic state in bilayer graphene: A first-principles investigation

The ground state of bilayer graphene is investigated using density functional calculations with a local spin-density approximation. We find a ground state with layer antiferromagnetic ordering, which is one of the candidate states suggested by former studies based on a simplified model. The calculations prove that the layer antiferromagnetic state is stable even if the nonlocal Coulomb interaction and the remote hopping are included. The gap of the correlated ground state is about 1.8 meV, in reasonable agreement with the experimental value. The surface magnetism in the bilayer graphene is of the order of 10(-2)mu(B)/nm(2).