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Title: Electronic Structure of Doped Lanthanum Cuprates Studied with Resonant Inelastic X-Ray Scattering

Journal Article · · Physical Review. B, Condensed Matter and Materials Physics
OSTI ID:1033197

We report a comprehensive Cu K-edge resonant inelastic x-ray scattering (RIXS) investigation of La{sub 2-x}Sr{sub x}CuO{sub 4} (LSCO) for 0 {le} x {le} 0.35, stripe-ordered La{sub 1.875}Ba{sub 0.125}CuO{sub 4} (LBCO), and La{sub 2}Cu{sub 0.96}Ni{sub 0.04}O{sub 4} (LCNO) crystals. The RIXS spectra measured at three high-symmetry momentum-transfer (q) positions are compared as a function of doping and for the different dopants. The spectra in the energy range 1-6 eV can be described with three broad peaks, which evolve systematically with increased doping. The most systematic trend was observed for q = ({pi},0) corresponding to the zone boundary. As hole doping increased, the spectral weight transfer from high energies to low energies is nearly linear with x at this q. We interpret the peaks as interband transitions in the context of existing band models for this system, assigning them to Zhang-Rice band {yields} upper Hubbard band, lower-lying band {yields} upper Hubbard band, and lower-lying band {yields} Zhang-Rice band transitions. The spectrum of stripe-ordered LBCO was also measured, and found to be identical to the correspondingly doped LSCO, except for a relative enhancement of the near-infrared peak intensity at {approx}1.5-1.7 eV. The temperature dependence of this near-infrared peak in LBCO was more pronounced than for other parts of the spectrum, continuously decreasing in intensity as the temperature was raised from 25 to 300 K. Finally, we find that 4% Ni substitution in the Cu site has a similar effect on the spectra as does Sr substitution in the La site.

Research Organization:
Brookhaven National Lab. (BNL), Upton, NY (United States)
Sponsoring Organization:
DOE - OFFICE OF SCIENCE
DOE Contract Number:
DE-AC02-98CH10886
OSTI ID:
1033197
Report Number(s):
BNL-94570-2011-JA; R&D Project: PO-011; KC0202010; TRN: US1200297
Journal Information:
Physical Review. B, Condensed Matter and Materials Physics, Vol. 83, Issue 7; ISSN 1098-0121
Country of Publication:
United States
Language:
English