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

TL;DR

This RIXS study reveals how charge excitations in Nd1.85Ce0.15CuO4 depend on momentum, showing distinct intraband and interband behaviors, with results aligning with Hubbard model calculations.

Contribution

First separation of intraband and interband charge excitations in electron-doped cuprates using RIXS, revealing their momentum dependence and dispersion characteristics.

Findings

Intraband excitation shows clear dispersion with q-dependent width.

Interband excitation is concentrated around 2 eV near the zone center.

Experimental results agree with Hubbard model calculations.

Abstract

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