INTERMEDIATE-TEMPERATURE ORDERING IN A 3-STATE ANTIFERROMAGNETIC POTTS-MODEL

We investigate the ordering in a three-state antiferromagnetic Potts m odel on a simple cubic lattice by using an efficient cluster-flipping Monte Carlo algorithm. By considering the degeneracy due to the sublat tices in two different ways, we arrive at two entirely different phase s [rotationally symmetric (RS) and permutationally symmetric sublattic e (PSS)] for the intermediate temperature region. Each of these phases has been claimed to be the correct phase by different authors in a re cent controversy over ordering in this system. We show that the system moves from a broken sublattice symmetry phase at low temperature to t he disordered phase by going through the RS phase at intermediate temp erature, and that the PSS phase results from taking the sublattice deg eneracy into account in an incorrect fashion. [S0163-1829(98)03738-2].