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Doping dependence of charge-transfer excitations in La_{2-x}Sr_xCuO_4

Young-June Kim·J. P. Hill·Seiki Komiya·Yoichi Ando·D. Casa·T. Gog·C. T. Venkataraman
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Abstract

We report a resonant inelastic x-ray scattering (RIXS) study of the doping dependence of charge-transfer excitations in $\rm La_{2-x}Sr_xCuO_4$. The mome ntum dependence of these charge excitations are studied over the whole Brillouin zone in underdoped (x=0.05) and optimally doped (x=0.17) samples, and compared with that of the undoped (x=0) sample. We observe a large change in the RIXS spectra between the x=0 and x=0.17 sample, while the RIXS spectra of the x=0.05 sample are similar to that of the x=0 sample. The most prominent effect of doped-holes on the charge excitation spectra is the appearance of a continuum of intensity, which exhibits a strong momentum-dependence below 2 eV. For the x=0.17 sample, some of the spectral weight from the lowest-lying charge-transfer excitation of the undoped compound is transferred to the continuum intensity below the gap, in agreement with earlier optical studies. However, the higher energy charge-transfer excitation carries significant spectral weight even for the x=0.17 sample. The doping dependence of the dispersion of this charge-transfer excitation is also discussed and compared with recent theoretical calculations.

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Young-June Kim, J. P. Hill, Seiki Komiya, Yoichi Ando, D. Casa, T. Gog, C. T. Venkataraman. 2004-07-14. Doping dependence of charge-transfer excitations in La_{2-x}Sr_xCuO_4. https://doi.org/10.1103/physrevb.70.094524

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