  Tight binding electrons on a honeycomb lattice are described by an effective
Dirac theory at low energies. Lowering symmetry by an alternate ionic potential
($\Delta$) generates a single-particle gap in the spectrum. We employ the
dynamical mean field theory (DMFT) technique, to study the effect of on-site
electron correlation ($U$) on massive Dirac fermions. For a fixed mass
parameter $\Delta$, we find that beyond a critical value $U_{c1}(\Delta)$
massive Dirac fermions become massless. Further increasing $U$ beyond
$U_{c2}(\Delta)$, there will be another phase transition to the Mott insulating
state. Therefore the competition between the single-particle gap parameter,
$\Delta$, and the Hubbard $U$ restores the semi-metallic nature of the parent
Hamiltonian. The width of the intermediate semi-metallic regime shrinks by
increasing the ionic potential. However, at small values of $\Delta$, there is
a wide interval of $U$ values for which the system remains semi-metal.
