Superconductivity has recently been discovered in Pr2Ba4Cu7O15−δ with a maximum Tc of about 15K. Since the CuO planes in this material are believed to be insulating, it has been proposed that the superconductivity occurs in the double (or zigzag) CuO chain layer. On phenomenological grounds, we propose a theoretical interpretation of the experimental results in terms of a new phase for the zigzag chain, labelled by C1S3/2. This phase has a gap for some of the relative spin and charge modes but no total spin gap, and can have a divergent superconducting susceptibility for repulsive interactions. A microscopic model for the zigzag CuO chain is proposed, and on the basis of density matrix renormalization group (DMRG) and bosonization studies of this model, we adduce evidence that supports our proposal.
@article{arxiv.0708.3888,
title = {Superconductivity in zigzag CuO chains},
author = {Erez Berg and Theodore H. Geballe and Steven A. Kivelson},
journal= {arXiv preprint arXiv:0708.3888},
year = {2008}
}