  We demonstrate that the phenomenon of current confinement along graphene n-p
junctions at high magnetic fields can be used to form an Aharonov-Bohm
interferometer. The interference system exploits a closed n-p junction that can
be induced by a floating gate within the sample, and coupling of the junction
currents with the edge currents in the quantum Hall regime. Operation of the
device requires current splitting at the edge and the n-p junction contacts
which is found for armchair ribbons at low Fermi energy.
