Singlet pairing and superconductivity in t-J ladders with Mott insulating stripes

TL;DR

This paper demonstrates that strong correlations in t-J ladder systems with Mott insulating stripes can induce a novel singlet-pair superconducting phase, where pairing is mediated by antiferromagnetic correlations.

Contribution

It introduces a new superconducting phase in ladder geometries with Mott stripes, analyzed via density matrix renormalization group methods.

Findings

Negative binding energies indicate pairing.

Algebraically decaying interleg singlet-pair correlations show superconductivity.

Antiferromagnetic correlations act as the pairing mechanism.

Abstract

Pairing in superconductors occurs in a variety of channels and can be produced by various mechanisms. Here, we show that, in the presence of strong correlations, a novel singlet-pair superconducting phase can occur in ladder geometries with the fermions in the pairs residing on different sides of a Mott insulating stripe. The antiferromagnet correlations in the Mott stripe provide the pairing "glue" in such a phase. We study, using the density matrix renormalization group method, the ground state of four-leg t-J ladders with Mott insulating stripes in the inner two legs. Pairing and superconductivity are revealed by the presence of negative binding energies and by algebraically decaying interleg singlet-pair correlations, respectively.