Enhancement of superconducting correlation due to interlayer tunneling.

TL;DR

This paper investigates how interlayer tunneling enhances superconductivity in layered cuprates by suppressing magnetic order and promoting gapless regions in the Fermi surface, leading to higher critical temperatures.

Contribution

It demonstrates that non-zero interlayer tunneling optimizes superconductivity by modifying magnetic order and creating favorable conditions for the spin bag mechanism.

Findings

Interlayer tunneling suppresses in-plane magnetic SDW order.

Superconductivity is enhanced in gapless Fermi surface regions.

Maximum $T_c$ occurs at non-zero interlayer tunneling $t_{ot}$.

Abstract

Interlayer single particle tunneling between the $Cu-O$ layers suppress the in-plane short range magnetic order (which is modeled as spin density wave (SDW) insulator). Doping over the SDW state kills perfect nesting of the Fermi surface (FS) in certain directions and hence SDW gap reduces to zero in those directions of the FS. Coupling between the planes through interlayer tunneling ($t_{\perp}$) further suppresses the in-plane magnetic SDW-gap and hence becomes anisotropic. Superconductivity arises in the gapless regions of the FS under the `modified spin bag' mechanism. We show that the highest $T_c$ can only be obtained for non-zero $t_{\perp}$ based on this mechanism.