arXiv:cond-mat/9605148 · Physical review. B, Condensed matter
Mean-field analysis of antiferromagnetic three-state Potts model with next-nearest-neighbor interaction
Mitsuhiro Itakura
Abstract
The three-state Potts model with antiferromagnetic nearest-neighbor (NN) and ferromagnetic next-nearest-neighbor (NNN) interaction is investigated within a mean-field theory. We find that the phase diagram contains two kinds of ordered phases, the so-called broken-sublattice-symmetry and permutationally-symmetric-sublattice phases, separated by a discontinuous phase transition line. The order-disorder transition is continuous for weak NNN interactions and becomes a discontinuous transition, via a tricritical point, when the strength of the NNN interaction is increased.