Comment on "Variation of the superconducting transition temperature of hole-doped copper oxides"

TL;DR

This paper critiques a previous derivation of the gap equation in the interlayer tunneling model for multilayered cuprates, emphasizing the importance of local k-space structure and nonuniform hole distribution for accurate Tc predictions.

Contribution

It identifies errors in prior derivations of the ILT model and highlights the significance of local k-space structure and layer-specific hole distribution in understanding high-Tc behavior.

Findings

Incorrect derivation of the gap equation in previous ILT model work.

Failure of previous models to account for local k-space structure.

Importance of nonuniform hole distribution among layers.

Abstract

We point out the incorrect derivation of the gap equation in X.-J. Chen and H. Q. Lin [Phys. Rev. B 69 (2004) 104518; cond-mat/0306680] within the interlayer tunneling (ILT) model for multilayered cuprates. There, the local structure in k-space of the ILT effective interaction has not been taken into due account when the ILT model is generalized to the case of n layers per unit cell. This is a specific characteristic of the ILT model that, apart from giving rise to a highly nontrivial k-dependence of the gap function, is known to enhance the critical temperature Tc in a natural way. As a consequence, we argue that Chen and Lin's results cannot be employed, in their present form, for a quantitative interpretation of the high-pressure dependence of Tc in Bi-2212, as is done by X.-J. Chen et al. [cond-mat/0408587]. Moreover, when the generalization of X.-J. Chen et al. [cond-mat/0408587] is applied to the case n=2, it fails to reproduce the original ILT gap equation. However, a more careful analysis of the ILT model for multilayered cuprates, taking into account the nonuniform hole distribution among inequivalent layers, has been earlier suggested to describe the observed pressure dependence of Tc in homologous series of high-Tc cuprates.