$\eta$-pairing as a mechanism of superconductivity in models of strongly correlated electrons

TL;DR

This paper demonstrates that extended Hubbard models with additional interactions can exhibit superconductivity in their ground state across various dimensions, even with moderate repulsive interactions.

Contribution

It shows that a broad class of extended Hubbard models can have superconducting ground states, providing insights into mechanisms of superconductivity in strongly correlated systems.

Findings

Superconducting ground states found in extended Hubbard models.

Superconductivity persists even with moderate repulsive interactions.

Complete phase diagrams obtained in some special cases.

Abstract

We consider extended versions of the Hubbard model which contain additional interactions between nearest neighbours. In this letter we show that a large class of these models has a superconducting ground state in arbitrary dimensions. In some special cases we are able to find the complete phase diagram. The superconducting phase exist even for moderate repulsive values of the Hubbard interaction $U$.