The incommensurate charge-density-wave instability in the extended three-band Hubbard model

TL;DR

This paper investigates charge-density-wave instabilities in an extended three-band Hubbard model relevant to cuprate superconductors, revealing incommensurate charge order as a dominant instability preceding valence transitions, with implications for pairing and normal state anomalies.

Contribution

It demonstrates that incommensurate charge-density-waves dominate over valence instabilities in an extended Hubbard model with long-range interactions, highlighting their role in high-temperature superconductivity.

Findings

Incommensurate charge-density-waves occur before valence instability.

Long-range Coulomb interactions influence charge instabilities.

Charge-density-waves induce effective attraction related to pairing.

Abstract

The infinite-U three-band Hubbard model is considered in order to describe the CuO_2 planes of the high temperature superconducting cuprates. The charge instabilities are investigated when the model is extended with a nearest-neighbor repulsion between holes on copper d and oxygen p orbitals and in the presence of a long-range Coulombic repulsion. It is found that a first-order valence instability line ending with a critical point is present like in the previously investigated model without long-range forces. However, the dominant critical instability is the formation of incommensurate charge-density-waves, which always occur before the valence-instability critical point is reached. An effective singular attraction arises in the proximity of the charge-density wave instability, accounting for both a strong pairing mechanism and for the anomalous normal state properties.