  We investigate the transport properties of massive Dirac fermions subjected
to uncorrelated scalar potential disorder, and mass disorder. Using a finite
difference method, the conductance is calculated for a wide variety of
combinations of these two disorder strengths. By calculating the scaling of
conductivity with system size we find that, depending on the combination, the
system can have an insulating, scale invariant, and metallic behavior. We
identify the critical values of these disorder strengths where the phase
transitions occur. We study both the zero and nonzero average mass cases to
examine the effect of scalar potential disorder on band gap. Our results
suggest a suppression of the band gap by the scalar potential disorder.
