Temperature dependence of the electronic structure of SrCuO studied by resonant inelastic X-ray scattering

Yoshida, Masahiro; Ishii, Kenji; Ikeuchi, Kazuhiko*; Jarrige, I.; Murakami, Yoichi*; Mizuki, Junichiro; Tsutsui, Kenji; Toyama, Takami*; Maekawa, Sadamichi*; Kudo, Kazutaka*; Koike, Yoji*; Endo, Yasuo*

SrCaCuO (SCCO), which is composed of two-leg ladders and edge-sharing chains, is the first superconducting cuprate without CuO planes. By substituting Ca for Sr, holes are transferred from the chains to the ladders. It was recently shown that charge ordering (CO) along the leg direction in the ladder occurs at and the periodicity is five times the unit length along the c axis. In order to investigate the electronic excitations associated with the CO, we carried out resonant inelastic X-ray scattering (RIXS) experiments for SCCO (). Cu- RIXS can directly probe the momentum-dependent electronic excitations related to the Cu site, which are resonantly enhanced by tuning the incident photon energy to the Cu -edge. We measured the q dependence of the intraband excitations, which is associated with the dynamics of doped holes in the Zhang-Rice singlet band. The intensity is enhanced at the momentum corresponding to the periodicity of the CO in , while the temperature dependence of the enhancement is different for and . We discuss the relationship between our experimental results and the occurrence of the CO.