Momentum Dependence of Charge Excitations in the Electron-Doped Superconductor Nd1.85Ce0.15CuO4: a RIXS Study

摘要

We report a resonant inelastic x-ray scattering (RIXS) study of chargeexcitations in the electron-doped high-Tc superconductor Nd1.85Ce0.15CuO4. Theintraband and interband excitations across the Fermi energy are separated forthe first time by tuning the experimental conditions properly to measure chargeexcitations at low energy. A dispersion relation with q-dependent width emergesclearly in the intraband excitation, while the intensity of the interbandexcitation is concentrated around 2 eV near the zone center. The experimentalresults are consistent with theoretical calculation of the RIXS spectra basedon the Hubbard model.