# Decrease of d-wave pairing strength in spite of the persistence of magnetic excitations in the overdoped Hubbard model

## TL;DR

This study uses quantum Monte Carlo simulations of the Hubbard model to show that despite persistent high-energy magnetic excitations in overdoped cuprates, the reduction in pairing strength is due to decreased spectral weight at large momentum transfer, explaining the decline in superconducting transition temperature.

## Contribution

The paper demonstrates that the decrease in d-wave pairing strength in overdoped cuprates is caused by reduced spectral weight at large momentum transfer, despite the persistence of magnetic excitations.

## Key findings

- High energy magnetic excitations persist in overdoped regime.
- Reduced spectral weight at large momentum transfer diminishes pairing strength.
- The decrease in $T_c$ is linked to spectral weight loss, not excitation presence.

## Abstract

Evidence for the presence of high energy magnetic excitations in overdoped La$_{2-x}$Sr$_x$CuO$_4$ (LSCO) has raised questions regarding the role of spin-fluctuations in the pairing mechanism. If they remain present in overdoped LSCO, why does $T_c$ decrease in this doping regime? Here, using results for the dynamic spin susceptibility ${\rm Im}\chi(q,\omega)$ obtained from a determinantal quantum Monte Carlo (DQMC) calculation for the Hubbard model we address this question. We find that while high energy magnetic excitations persist in the overdoped regime, they lack the momentum to scatter pairs between the anti-nodal regions. It is the decrease in the spectral weight at large momentum transfer, not observed by resonant inelastic X-ray scattering (RIXS), which leads to a reduction in the $d$-wave spin-fluctuation pairing strength.