ANTIFERROMAGNETIC PHASE-TRANSITION AND CROSSOVER TO FERMI-LIQUID PHASE IN A WEAKLY COUPLED HALF-FILLED CHAIN SYSTEM

Effects of the intrachain electron-electron umklapp process and the in terchain one-particle hopping, II, in a weakly coupled half-filled cha in system have been studied, based on the perturbative renormalization -group approach. By solving the scaling equations, we found that the i ntrachain umklapp process strongly suppresses an interchain one-partic le process and causes a finite critical value for t(perpendicular to), t(perpendicular to c). For t(perpendicular to) < t(perpendicular to c ), as the temperature decreases, the system undergoes a phase transiti on into an antiferromagnetic long-range-ordered phase at a transition temperature T-N which increases with the increasing t(perpendicular to ). On the other hand, for t(perpendicular to) > t(perpendicular to c), the system undergoes a crossover to the Fermi liquid phase where the interchain coherent propagation of quasi-particles occurs.