Effect of nonuniform hole-content distribution within the interlayer pair-tunneling mechanism of layered HTSC

TL;DR

This paper investigates how nonuniform hole distribution among layers influences the critical temperature in layered high-temperature superconductors, extending the ILT model to multiple layers and comparing predictions with experimental data.

Contribution

It generalizes the ILT model to multilayer systems with inequivalent layers, analyzing the impact of nonuniform hole distribution on Tc.

Findings

Nonuniform hole distribution significantly affects Tc.

Inner or outer layers can dominate superconductivity depending on doping.

Model predictions align with experimental Tc data under pressure.

Abstract

The interlayer pair-tunneling (ILT) mechanism for high-$T_c$ superconductivity is able to predict the dependence of the (optimal) critical temperature Tc on the number of layers n within an homologous series of layered cuprate oxides. We generalize the mean-field procedure employed to evaluate Tc within an extended in-plane Hubbard model in presence of ILT, developed for a bilayer complex (n = 2), to the case of n = 3, 4 inequivalent superconducting layers. As a function of doping, we show how a nonuniform hole-content distribution among different layers affects Tc. In particular, depending on doping, the onset of superconductivity may be ruled by inner or outer layers. The latter result may be related to recent experimental data of Tc as a function of pressure in Tl- and Bi-based layered superconductors.