PHASE-STRUCTURE OF QED3 AT FINITE TEMPERATURE

Dynamical symmetry breaking in three-dimensional QED with N fermion flavours i s considered at finite temperature, in the large N approximation. Using an approximate treatment of the Schwinger-Dyson equation for the fermion self-energy, we find that chiral symmetry is restored above a certain critical temperature which depends itself on N. We find that the ratio of the zero-momentum-zero-temperature fermion mass to the critical temperature has a large value compared with four-fermion theories, as had been suggested in a previous work with a momentum-independent self-energy. Evidence of a temperature-dependent critical N is shown to appear in this approximation. The phase diagram for spontaneous mass generation in the theory is presented in T-N space.