Monte Carlo Study of an Extended 3-State Potts Model on the Triangular   Lattice
  By introducing a chiral term into the Hamiltonian of the 3-state Potts model on a triangular lattice additional symmetries are achieved between the clockwise and anticlockwise states and the ferromagnetic state. This model is investigated using Monte Carlo methods. We investigate the full phase diagram and find evidence for a line tricritical points separating the ferromagnetic and antiferromagnetic phases. 
Z.F. Wang, B.W. Southern and D.A. Lavis