One-dimensional t-J model with next-nearest-neighbor hopping: Breakdown of the Luttinger liquid

We investigate the effect of a next-nearest-neighbor hopping integral t' in the one-dimensional t-J model, using Lanczos diagonalization of finite chains. Even moderate values of t' have a dramatic effect on the dynamical correlation functions and Fermi-surface topology. The high-energy holon bands become diffuse and overdamped, and the band structure near the Fermi energy is dominated by t'. With increasing hole concentration the system undergoes a phase transition that changes the volume of the Fermi surface, but neither phase has a k(F) compatible with a Luttinger liquid.