  We investigate, analytically and numerically, the effects of disorder on the
density of states and on the localization properties of the relativistic two
dimensional fermions in the lowest Landau level. Employing a supersymmetric
technique, we calculate the exact density of states for the Cauchy (Lorentzian)
distribution for various types of disorders. We use a numerical technique to
establish the localization-delocalization (LD) transition in the lowest Landau
level. For some types of disorder the LD transition is shown to belong to a
different universality class, as compared to the corresponding nonrelativistic
problem. The results are relevant to the integer quantum Hall plateau
transitions observed in graphene.
