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

D. C. Peets; D. G. Hawthorn; K. M. Shen; Young-June Kim; D. S. Ellis; H. Zhang; Seiki Komiya; Yoichi Ando; G. A. Sawatzky; Ruixing Liang; D. A. Bonn; W. N. Hardy

doi:10.1103/physrevlett.103.087402

arXiv · 0905.1241

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

D. C. Peets·D. G. Hawthorn·K. M. Shen·Young-June Kim·D. S. Ellis·H. Zhang·Seiki Komiya·Yoichi Ando·G. A. Sawatzky·Ruixing Liang·D. A. Bonn·W. N. Hardy

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Abstract

X-ray absorption spectra on the overdoped high-temperature superconductors Tl_2Ba_2CuO_{6+delta} (Tl-2201) and La_{2-x}Sr_xCuO_{4+delta} (LSCO) reveal a striking departure in the electronic structure from that of the underdoped regime. The upper Hubbard band, identified with strong correlation effects, is not observed on the oxygen K edge, while the lowest-energy prepeak gains less intensity than expected above p ~ 0.21. This suggests a breakdown of the Zhang-Rice singlet approximation and a loss of correlation effects or a significant shift in the most fundamental parameters of the system, rendering single-band Hubbard models inapplicable. Such fundamental changes suggest that the overdoped regime may offer a distinct route to understanding in the cuprates.

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D. C. Peets, D. G. Hawthorn, K. M. Shen, Young-June Kim, D. S. Ellis, H. Zhang, Seiki Komiya, Yoichi Ando, G. A. Sawatzky, Ruixing Liang, D. A. Bonn, W. N. Hardy. 2009-05-08. Measurement of x-ray absorption spectra of overdoped high-temperature cuprate superconductors: Inapplicability of the single-band Hubbard model. https://doi.org/10.1103/physrevlett.103.087402

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