@article{8c6a0abcbfca43718d5544d4972b8dbf,
title = "Localized character of charge excitations for La2-xSrxNi O4+δ revealed by oxygen K-edge resonant inelastic X-ray scattering",
abstract = "We performed a resonant inelastic X-ray scattering (RIXS) study of La2-xSrxNiO4+δ (LSNO) at the oxygen K edge to investigate the nature of the doped holes with regard to charge excitations. Charge excitations of the hole-doped nickelates are found to be almost independent of momentum transfer, indicating that the doped holes are strongly localized in character. Additionally, conspicuous changes in energy position are in temperature dependence. These characters are observed in stark contrast to those of the high-Tc cuprate La2-xSrxCuO4 (LSCO), where delocalized doped holes form charge excitations with sizable momentum dependence in the CuO2 plane. This distinct nature of charge excitations of doped holes is consistent with the metallicity of the materials and could be caused by strong electron-phonon coupling and weak quantum spin fluctuation in the nickelates.",
author = "Kohei Yamagami and Kenji Ishii and Yasuyuki Hirata and Keisuke Ikeda and Jun Miyawaki and Yoshihisa Harada and Masanori Miyazaki and Shun Asano and Masaki Fujita and Hiroki Wadati",
note = "Funding Information: We thank K. Yamazoe and U. J. Ralph for supporting the experiments and K. Takubo for fruitful discussions. The resonant inelastic x-ray scattering measurements at SPring-8 BL07LSU were carried out as joint research by the Synchrotron Radiation Research Organization and the Institute for Solid State Physics, The University of Tokyo (Proposal No. 2018A7558). This work was performed under the Inter-University Cooperative Research Program of the Institute for Materials Research, Tohoku University (Proposal Nos. 16K0005, 17K0067, and 18K0064). This work was partially supported by JSPS KAKENHI (Grants No. 16H04004 and No. 19H05824), Japan. K.Y. would like to acknowledge the support from the Motizuki Fund of the Yukawa Memorial Foundation. Publisher Copyright: {\textcopyright} 2020 American Physical Society. ",
year = "2020",
month = oct,
day = "23",
doi = "10.1103/PhysRevB.102.165145",
language = "English",
volume = "102",
journal = "Physical Review B",
issn = "2469-9950",
publisher = "American Physical Society",
number = "16",
}