Vacuum structure of the ((psi)over-bar psi)(3)(2)-model, accounting for the magnetic field and chemical potential

The phase structure of a (2+1)-dimensional field theory with four-fermion interaction is investigated, accounting for the external magnetic field H and chemical potential mu. The existence of the critical curve mu = mu(c)(H) dividing the manifold of points (mu,H) into two regions is demonstrated. In one of the regions, the vacuum is chiral-symmetric and in the other, the symmetry is spontaneously broken. The behavior of the critical curve at large and small values of the external field is analyzed.