The Influence of Extended Interactions on Spin Dynamics in One-dimensional Cuprates

TL;DR

This paper investigates how extended interactions, such as long-range Coulomb and electron-phonon couplings, influence spin dynamics in one-dimensional cuprates, revealing their significant impact on spectral weight distribution and the importance of including them in models.

Contribution

The study demonstrates that extended interactions substantially alter the dynamical spin structure factor in 1D cuprates, highlighting their role beyond the standard Hubbard model.

Findings

Long-range interactions cause spectral weight redistribution in $S(q,)$.

Extended interactions significantly impact dynamical correlations.

$S(q,)$ can serve as an experimental probe for key interactions.

Abstract

Quasi-one-dimensional (1D) materials provide a unique platform for understanding the importance and influence of extended interactions on the physics of strongly correlated systems due to their relative structural simplicity and the existence of powerful theoretical tools well-adapted to one spatial dimension. Recently, this was highlighted by anomalous observations in the single-particle spectral function $A(q,\omega)$ of 1D cuprate chain compounds, measured by angle-resolved photoemission spectroscopy (ARPES), which were explained by the presence of a long-range attractive interaction. Such an extended interaction should leave its fingerprints on other observables, notably the dynamical spin structure factor $S(q,\omega)$, measured by neutron scattering or resonant inelastic x-ray scattering (RIXS). Starting from a simple Hubbard Hamiltonian in 1D and using time-dependent density matrix renormalization group (tDMRG) methods, we show that the presence of long-range attractive coupling, directly through an instantaneous Coulomb interaction $V$ or retarded electron-phonon ({\it el-ph}) coupling, can introduce significant spectral weight redistribution in $S(q,\omega)$ across a wide range of doping. This underscores the significant impact that extended interactions can have on dynamical correlations among particles, and the importance of properly incorporating this influence in modeling. Our results demonstrate that $S(q,\omega)$ can provide a sensitive experimental constraint, which complements ARPES measurements, in identifying key interactions in 1D cuprates, beyond the standard Hubbard model.