Dynamical Generation of Fermion Mass and Magnetic Field in Three-Dimensional QED with Chern-Simons Term

Abstract

We study dynamical symmetry breaking in three-dimensional QED with a Chern-Simons (CS) term, considering the screening effect of $N$ flavor fermions. We find a new phase of the vacuum, in which both the fermion mass and a magnetic field are dynamically generated, when the coefficient of the CS term $\kappa$ equals $N{e}^2/4\pi$. The resultant vacuum becomes the finite-density state half-filled by fermions. For $\kappa =N{e}^2/2\pi$, we find the fermion remains massless and only the magnetic field is induced. For $\kappa =0$, spontaneous magnetization does not occur and should be regarded as an external field.

Comments: 8 pages, no figure, to be published in Phys. Rev. Lett