  We report an atomically-precise integration of individual nitrogen (N) dopant
as an in-plane artificial nucleus in a graphene device by atomic implantation
to probe its gate-tunable quantum states and correlation effects. The N dopant
creates the characteristic resonance state in the conduction band, revealing a
giant carrier-dependent energetic renormalization up to 350 meV with respect to
the Dirac point, accompanied by the observation of long-range screening
effects. Joint density functional theory and tight-binding calculations with
modified perturbation potential corroborate experimental findings and highlight
the short-range character of N-induced perturbation.
