2005/06/30 by S. Wakimoto, Shuichi Wakimoto, Young‐June Kim +6 · 2 citations
Earth and Planetary Sciences · Physics and Astronomy · #Advanced Condensed Matter Physics #High-pressure geophysics and materials #Physics of Superconductivity and Magnetism #cond-mat.str-el #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.72.224508
published as Phys. Rev. B 72, 224508 (2005) · 7 pages, 7 figures
openalex publication_date 2005/12/14 · arxiv created 2005/12/16 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
Resonant inelastic x-ray scattering (RIXS) at the copper K absorption edge has been performed for heavily overdoped samples of La_2\ensuremath-xSrxCuO4 with x=0.25 and 0.30. We have observed the charge-transfer and molecular-orbital excitations, which exhibit resonances at incident energies of Ei=8.992 and 8.998\phantom\rule0.3em0exkeV, respectively. From a comparison with previous results on undoped and optimally doped samples, we determine that the charge-transfer excitation energy increases monotonically as doping increases. In addition, the Ei dependences of the RIXS spectral weight and absorption spectrum exhibit no clear peak at Ei=8.998\phantom\rule0.3em0exkeV in contrast to results in the underdoped samples. The low-energy (\ensuremath\leqslant3\phantom\rule0.3em0exeV) continuum excitation intensity has been studied utilizing the high-energy resolution of 0.13\phantom\rule0.3em0exeV (full width at half maximum). A comparison of the RIXS profiles at (\ensuremathπ\phantom\rule0.3em0ex0) and (\ensuremathπ\phantom\rule0.3em0ex\ensuremathπ) indicates that the continuum intensity exists even at (\ensuremathπ\phantom\rule0.3em0ex\ensuremathπ) in the overdoped samples, whereas it has been reported only at (0 0) and (\ensuremathπ\phantom\rule0.3em0ex0) for the x=0.17 sample. Furthermore, we also found an additional excitation on top of the continuum intensity at the (\ensuremathπ\phantom\rule0.3em0ex\ensuremathπ) and (\ensuremathπ\phantom\rule0.3em0ex0) positions.