Are the high-Tc superconductors strongly correlated electron systems?

TL;DR

This paper challenges the classification of high-Tc superconductors as strongly correlated electron systems, arguing that existing models are inadequate and proposing a new framework where electron interactions are negligible.

Contribution

It introduces a novel perspective that high-Tc superconductivity can be understood without strong electron correlations, contrasting with traditional models.

Findings

Hubbard and t-J models are inadequate for high-Tc superconductivity

Superconducting phase can be described as an energy minimum state with suppressed electron interactions

Proposes a new theoretical framework for understanding high-Tc superconductors

Abstract

In this paper, we argue that the high-temperature superconductors do not belong to strong correlated electron systems. It is shown that both the two-dimensional Hubbard and t-J models are inadequate for describing high temperature superconductivity. In our opinion, a superconducting phase should be an energy minimum electronic state which can be described in a new framework where the electron-electron interactions (both on-site Hubbard term and off-site term) and the electron-phonon interaction can be completely suppressed.