Momentum-resolved charge excitations in high- cuprates studied by resonant inelastic X-ray scattering

銅酸化物高温超伝導における運動量分解した電荷励起の共鳴非弾性X線散乱による研究

石井 賢司; Hoesch, M.*; 稲見 俊哉; 葛下 かおり*; 大和田 謙二; 坪田 雅己; 村上 洋一; 水木 純一郎; 遠藤 康夫; 筒井 健二*; 遠山 貴己*; 前川 禎通*; 山田 和芳*; 増井 孝彦*; 田島 節子*; 川嶋 浩和*; 秋光 純*

Ishii, Kenji; Hoesch, M.*; Inami, Toshiya; Kuzushita, Kaori*; Owada, Kenji; Tsubota, Masami; Murakami, Yoichi; Mizuki, Junichiro; Endo, Yasuo; Tsutsui, Kenji*; Toyama, Takami*; Maekawa, Sadamichi*; Yamada, Kazuyoshi*; Masui, Takahiko*; Tajima, Setsuko*; Kawashima, Hirokazu*; Akimitsu, Jun*

Resonant inelastic X-ray scattering (RIXS) in the hard X-ray regime is a new spectroscopic technique to measure electronic excitations utilizing brilliant synchrotron radiation. It has the great advantage that the momentum dependence can be measured unlike conventional optical methods. As inelastic neutron scattering gives spin or lattice dynamics, inelastic X-ray scattering can be a tool to measure charge dynamics in solids through the coupling of photon to the charge of the electron. Here, I would like to present our RIXS studies on high- cuprates and related materials which were performed in close collaboration with theorists. In doped Mott insulators, an interband excitation across the Mott gap and an intraband excitation below the gap are observed in the low energy region of RIXS spectra. Momentum and carrier-doping dependence of the excitations will be discussed.