Competition between stripes and pairing in at−t′−Jmodel

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 ${t-t}^{\prime }-J$ model in which a diagonal, single-particle, next-nearest-neighbor hopping $t^{\prime }$ is introduced. We find that this can suppress the formation of stripes and, for $t^{\prime }$ positive, enhance the $d_{x^2-y^2}$-like pairing correlations. The effect of $t^{\prime }>0\mathrm{}$ is to cause the stripes to evaporate into pairs and for $t^{\prime }<0\mathrm{}$ to evaporate into quasiparticles. Results for $n=4\mathrm{}$ and 6 $n$-leg ladders are discussed.