Failure oft−Jmodels in describing doping evolution of spectral weight in x-ray scattering, optical, and photoemission spectra of cuprates

Abstract

We have analyzed experimental evidence for an anomalous transfer of spectral weight from high to low energy scales in both electron and hole doped cuprates as a function of doping. X-ray scattering, optical and photoemission spectra are all found to show that the high energy spectral weight decreases with increasing doping at a rate much faster than predictions of the large U −limit calculations. The observed doping evolution is however well-described by an intermediate coupling scenario where the effective Hubbard U is comparable to the bandwidth. The experimental spectra across various spectroscopies are inconsistent with fixed-U exact diagonalization or quantum Monte Carlo calculations, and indicate a significant doping dependence of the effective U in the cuprates.

Investigation of particle-hole asymmetry in the cuprates via electronic Raman scattering

“…Recent comparisons of spectral weight transfer observed with ARPES, x-ray absorption, and optical spectra have been interpreted in terms of a doping dependent U . 20 This differs from the conclusion reached from many other studies of the Hubbard model.…”

Intermediate coupling model of the cuprates

“…Indeed, the rate of ASWT is found to increase monotonically as U decreases and, therefore, this rate can be used to quantify the degree of correlations in the cuprates. In a recent study [10], we compared ASWT in XAS, ARPES, and optical measurements, finding similar doping dependencies in all these spectroscopies for both electron-and hole-doped cuprates. The results are consistent with intermediate coupling values of U , Fig.…”

“…We describe the methodology underlying this quasiparticle-GW (QP-GW) scheme, and discuss its implications for various spectroscopies, casting this discussion in the broader context of current models of the cuprates. Our QP-GW self-energy reasonably captures in the cuprates the dressing of low-energy quasiparticles by spin and charge fluctuations, [3] the high-energy kink (HEK) seen in ARPES, [3] the residual high-energy Mott features in the optical spectra, [7] gossamer features, [9] anomalous spectral weight transfer (ASWT) with doping [10], and the magnetic resonance in neutron scattering. [11,12] Our model also captures a number of characteristic signatures of strong coupling physics of the Hubbard model, including suppression of double-occupancy, the t−J-model-like dispersions, spin-wave dispersion, and the 1/U scaling of the magnetic order.…”

Doping evolution of Zhang-Rice singlet spectral weight: A comprehensive examination by x-ray absorption spectroscopy

“…11 In principle, an effective doping dependent Hubbard U (p) is needed to fit the spectra weight. 11,20 Further comprehensive examinations at higher doping levels are certainly desirable.…”