Instability of the disordered critical points of Dirac fermions

Recently, in an attempt to study disordered criticality in quantum Hall systems and {ital d}-wave superconductivity, it was found that two-dimensional random Dirac-fermion systems contain a line of critical points that is connected to the pure system. We use bosonization and current algebra to study properties of the critical line and calculate the exact scaling dimensions of all local operators. We find that the critical line contains an infinite number of relevant operators with negative scaling dimensions. {copyright} {ital 1996 The American Physical Society.}