Effect of relevant umklapp process on the two-leg Hubbard ladder with a half-filled band under pressure

Abstract

By means of perturbative renormalization approach we study the effect of relevant umklapp process on dimensional crossover caused by interladder one particle hopping t _⊥ in weakly coupled two-leg Hubbard ladders with a half filled-band. We found that a crossover takes place at a finite value t _⊥ which increases as the amplitude of umklapp process increases. For t _⊥ < t _⊥c the system undergoes a phase transition to the spin density wave phase (SDW) via the two particle hopping process, while for t _⊥ > t _⊥c the system undergoes a crossover to the two dimensional Fermi liquid phase via one particle hopping process.