Competition between stripes and pairing in a t-t′-J model

As the number of legs n of an n-leg, t-J ladder increases, density-matrix renormalization group calculations have shown that the doped state tends to be characterized by a static array of domain walls and that pairing correlations are suppressed. Here we present results for a t-t'-J model in which a diagonal, single-particle, next-nearest-neighbor hopping t' is introduced. We find that this can suppress the formation of stripes and, for t' positive, enhance the d(x2-y2)-like pairing correlations. The effect of t' > 0 is to cause the stripes to evaporate into pairs and for t' < 0 to evaporate into quasiparticles. Results for n = 4 and 6 n-leg ladders are discussed.