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 interchain one-particle hopping, II, in a weakly coupled half-filled chain system have been studied, based on the perturbative renormalization-group approach. By solving the scaling equations, we found that the intrachain umklapp process strongly suppresses an interchain one-particle 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 transition 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.