Critical behavior of QED3 at finite temperature and density

Within a range of fermion masses and taking into account the influence of the chemical potential on the boson propagator, the dependence of the chiral susceptibility on temperature and chemical potential is investigated to gain insight in the phase transition of QED3. We show that, at high temperature, the system demonstrates a second-order phase transition characteristic in the chiral limit and illustrates a crossover beyond the chiral limit, while in the high density region it exhibits a first-order transition when the fermion mass is small but always reveals a crossover when the fermion mass exceeds a critical value mc. (orig.)