  We study the effect of disorder on the semimetal -- Mott insulator transition
in the half-filled repulsive Hubbard model on a honeycomb lattice, a system
that features vanishing density of states at the Fermi level. Using the
determinant quantum Monte Carlo method, we characterize various phases in terms
of the bulk-limit antiferromagnetic (AF) order parameter, compressibility, and
temperature-dependent DC conductivity. In the clean limit, our data are
consistent with previous results showing a single quantum critical point
separating the semi-metallic and AF Mott insulating phases. With the presence
of randomness, a non-magnetic disordered insulating phase emerges. Inside this
disordered insulator phase, there is a crossover from a gapless Anderson-like
insulator to a gapped Mott-like insulator.

Strongly Correlated Electrons;Disordered Systems and Neural Networks