PHASE-DIAGRAMS OF 2 GENERALIZED FK MODELS

We study two generalized FK models. The phase diagrams vary with the p eriod of the external potential D and with the amplitude of the pertur bation epsilon., Some novel and complex phase structures are found. Th ere are two threshold values of D for each model. Within different int ervals of D, the phase diagrams exhibit different behavior. (C) 1997 E lsevier Science B.V.