Journal of the Physical Society of Japan
Theory of Generalized 3-State Potts Model and Antiferromagnetic Potts Model
Takehiko Oguchi, Takuma Ishikawa, Haruo Yoshida
Abstract
The spin Hamiltonian with spin-1 system including a single parameter is proposed which expresses the 3-state Potts model (PM) or antiferromagnetic Potts model (AFPM) according as a value of the parameter. They are investigated by a new method which is the extension of the effective Hamiltonian method in a unified way. The first-order transition or the second-order transition are obtained for the PM or the AFPM, respectively. In the AFPM, the ordered phase has a residual entropy, nevertheless the ordered phase can exist stably.