Intermediate coupling model of cuprates: adding fluctuations to a weak coupling model of pseudogap and superconductuctivity competition

TL;DR

This paper models the pseudogap and superconductivity competition in cuprates by incorporating spin and charge fluctuations into a self-energy calculation, capturing many features traditionally attributed to strong correlations.

Contribution

It introduces an intermediate coupling model that adds fluctuations to a weak coupling framework, bridging the gap between mean-field results and strong correlation effects in cuprates.

Findings

Spectral functions show four subbands across doping levels.

Remnant Hubbard bands and in-gap spin-charge dressed bands identified.

Collapse of spin-density wave in overdoped regime.

Abstract

We demonstrate that many features ascribed to strong correlation effects in various spectroscopies of the cuprates are captured by a calculation of the self-energy incorporating effects of spin and charge fluctuations. The self energy is calculated over the full doping range from half filling to the overdoped system. In the normal state, the spectral function reveals four subbands: two widely split incoherent bands representing the remnant of the two Hubbard bands, and two additional coherent, spin- and charge-dressed in-gap bands split by a spin-density wave, which collapses in the overdoped regime. The resulting coherent subbands closely resemble our earlier mean-field results. Here we present an overview of the combined results of our mean-field calculations and the newer extensions into the intermediate coupling regime.