Poor screening and nonadiabatic superconductivity in correlated systems

TL;DR

This paper explores how electronic correlations affect screening and superconductivity in cuprates, demonstrating that reduced screening explains the phase diagram and nonadiabatic effects.

Contribution

It introduces an analytical Green's function model to quantify electronic correlation effects on screening and superconductivity in cuprates.

Findings

Reduced screening correlates with increased electronic correlation.

The model explains the cuprate $T_c$-$ ext{doping}$ phase diagram.

Experimental evidence supports the theoretical predictions.

Abstract

In this paper we investigate the role of the electronic correlation on the hole doping dependence of electron-phonon and superconducting properties of cuprates. We introduce a simple analytical expression for the one-particle Green's function in the presence of electronic correlation and we evaluate the reduction of the screening properties as the electronic correlation increases by approaching half-filling. The poor screening properties play an important role within the context of the nonadiabatic theory of superconductivity. We show that a consistent inclusion of the reduced screening properties in the nonadiabatic theory can account in a natural way for the $T_c$-$\delta$ phase diagram of cuprates. Experimental evidences are also discussed.