Comment on "Measurement of x-ray absorption spectra of overdoped high-temperature cuprate superconductors: Inapplicability of the single-band Hubbard model"

TL;DR

This paper critiques a recent claim that x-ray absorption saturation in overdoped cuprates invalidates the single-band Hubbard model, demonstrating instead that the data aligns with the model's predictions.

Contribution

The authors clarify that the observed x-ray absorption behavior in overdoped cuprates is consistent with the single-band Hubbard model, countering previous claims of its breakdown.

Findings

Data agrees quantitatively with the Hubbard model

Saturation does not imply model failure

Challenges previous interpretation of x-ray absorption results

Abstract

In a recent Letter, Peets, et al. measured the x-ray intensity at the oxygen K-edge in overdoped La$_{2-x}$Sr$_x$CuO$_{4\pm\delta}$ (LSCO) and Tl$_2$Ba$_2$CuO$_{6+\delta}$. They claimed that, unlike the underdoped samples of LSCO and YBa$_2$Cu$_3$O$_x$ in which the integrated intensity increases at least linearly with doping, it saturates abruptly for a hole count exceeding $x\approx 0.23$. They interpreted the saturation as a breakdown of the 1-band Hubbard model in the cuprates. However, we show that their results are in quantitative agreement with the 1-band Hubbard model.