Particle-hole asymmetry in the dynamical spin and charge structure factors of the corner-shared one-dimensional cuprates

TL;DR

This study investigates the doping-dependent spin and charge excitations in one-dimensional cuprates, revealing particle-hole asymmetries and the importance of oxygen orbitals for accurate modeling and interpretation of experimental data.

Contribution

It demonstrates that the singleband Hubbard model captures low-energy excitations but fails to account for orbital-resolved charge asymmetries, highlighting the need to include oxygen orbitals.

Findings

Singleband Hubbard model describes low-energy spin and charge excitations.

Interorbital spin excitations between Cu and O are significant.

Orbital-resolved charge excitations show particle-hole asymmetry.

Abstract

The collective spin and charge excitations of doped cuprates and their relationship to superconductivity are not yet fully understood, particularly in the case of the charge excitations. Here, we study the doping-dependent dynamical spin and charge structure factors of single and multi-orbital models for the one-dimensional corner shared spin-chain cuprates using several numerically exact methods. We find that the singleband Hubbard model can describe the spin and charge excitations of the $pd$-model in the low-energy region, including the particle-hole asymmetry in the spin response. However, our results also reveal that the weight of the interorbital spin excitations between Cu and O orbitals is comparable to the weight of the spin excitations between two Cu orbitals. This finding elucidates the microscopic nature of the spin excitations in the 1D cuprates and sheds light on the spin properties of other oxides. Importantly, we find a particle-hole asymmetry in the orbital-resolved charge excitations, which cannot be described by the singleband Hubbard model and is relevant to resonant inelastic x-ray scattering experiments. Our results imply that the explicit inclusion of the oxygen degrees of freedom may be required to understand experimental observations.