We have examined the critical properties of the q=6 clock (vector Potts) model in two dimensions through Monte Carlo simulations. The model was investigated on L×L square lattices of size L=4 to L=72 with periodic boundary conditions. We found an intermediate XY-like phase between a low-temperature ordered phase and a high-temperature disordered phase. The phase transitions occur at $k_B$$T_1$/J=0.68±0.02 and $k_B$$T_2$/J=0.92±0.01 and are of the Kosterlitz-Thouless type. The susceptibility diverges in the intermediate phase and the exponent η varies between 0.100 at $T_1$ and 0.275 at $T_2$.

• Received 24 June 1985

DOI:https://doi.org/10.1103/PhysRevB.33.437