Carrier dynamics in doped cuprates studied by Cu K-edge RIXS

銅K吸収端の共鳴非弾性X線散乱によるドープされた銅酸化物の電荷ダイナミクスの研究

石井 賢司

Ishii, Kenji

Carrier doping often induces significant change of the electronic properties of Mott insulators and behavior of the doped carriers is one of the central issues in strongly correlated electron systems. Doped cuprates is a suitable system for studying the carrier dynamics because their electronic structure near the Fermi energy can be described by a limited number of electronic orbitals. While spin dynamics of the doped cuprates has been extensively studied by inelastic neutron scattering and more recently by Cu L-edge RIXS, Cu K-edge RIXS stands for a tool for measuring charge dynamics. I will present here Cu K-edge RIXS studies focusing on the charge dynamics in doped cuprates. Recently, a dispersive excitation below the charge-transfer gap was observed in the hole-doped cuprates, LaSrCuO and BiPbSrCuO, by appropriately selecting the resonant condition. Momentum dependence of the excitation is similar to that in the electron-doped cuprate NdCeCuO. Because RIXS intensity at the resonant condition can be ascribed to the dynamical charge correlation function, this result is an experimental evidence of the similarity of the charge correlation function between hole- and electron-dope systems.