In-plane oxygens in high-temperature superconducting cuprates

TL;DR

This paper investigates the crucial role of in-plane oxygen atoms in high-temperature cuprate superconductors, emphasizing their influence on electronic states, magnetic responses, and charge order, and highlights the need for further experimental and theoretical studies.

Contribution

It provides a detailed analysis of oxygen's role in cuprates, integrating structural and photoemission data, and proposes a magnetic interaction-based scenario for charge order in LBCO.

Findings

Oxygen contributes predominantly to the metallic states along the Fermi surface.

Incommensurate magnetic responses can be explained by separate roles of oxygen and copper.

Charge order in LBCO may be driven by magnetic interactions within the plane.

Abstract

The role of the oxygen degree of freedom in the cuprates' superconducting planes is analyzed in detail. Structural and photoemission results are reviewed to show that the most sparse description of the in-plane electronic states requires explicit control of the oxygens. For metallic states, the relative contributions of oxygen and copper vary along the Fermi surface, with the arc metallicity dominantly oxygen-derived. For the magnetic responses, we find that the observed incommensurability arises naturally if one keeps separate the roles of the two sites. For the charge order in LBCO, we propose a scenario, based on magnetic interactions in the plane. We stress the need for further experimental investigations of the evolution of the intracell charge distribution with doping, and for a better theoretical understanding of the large particle-hole-symmetry breaking required for successful phenomenologies, but difficult to reconcile with ab initio calculations.