Dynamical Effects of Chern-Simons Term

We study how the Chern-Simons term effects the dynamically generated fermion mass in $(2+1)D$ Quantum Electrodynamics in the framework of large $N$ expansion. We find that when the Chern-Simons term is present half of the fermions get mass $M+m$ and half get $M-m$. The parity-preserving mass $m$ is generated only when $N<\tilde{N}_c$. Both the critical number, $\tilde{N}_c$, of fermion flavor and the magnitude, $m$, reduce when the effect of the Chern-Simons term dominates.