Evolution from intralayer to interlayer superconductivity in a bilayer ladder
Phys. Rev. B 114, 225122 – Published 13 October, 2026
DOI: https://doi.org/10.1103/hhh7-fb39
Abstract
Motivated by the bilayer cuprate superconductors and nickelate superconductor , we investigate the evolution from intralayer to interlayer superconductivity (SC) in finite-width bilayer ladders, where is the in-plane electron hopping, is the in-plane spin interaction, and is the interplane spin interaction. By means of density matrix renormalization group calculations, we map out the quantum phase diagram of the bilayer two-leg ladders by tuning in a large doping range . We find that a large can always drive interlayer SC by coupling the two layers in both the Luther-Emery liquid (LEL) and Luttinger liquid states. By coupling two LEL states, the in-plane SC evolves to interplane SC either through an intermediate charge-density-wave (CDW) phase or directly, depending on doping ratio. This emergent CDW phase, which exists over a finite doping range, appears to develop from the CDW state of the two-leg ladder at . By coupling two Luttinger liquids, the in-plane Luttinger liquids show a transition to the interplane superconducting phase at large , as reported in previous literature. Interestingly, in the intermediate regime, we find that, while the in-plane Luttinger liquid features remain stable, the interplane SC can develop an enhanced quasi-long-range order with the power exponent . Finally, we show that the interlayer SC is also stable by coupling the bilayer three-leg ladders by a strong interaction, from both the LEL and Luttinger liquid states.