# Observation of a dispersive charge mode in hole-doped cuprates using resonant inelastic x-ray scattering at the oxygen K edge

## TL;DR

This study uses resonant inelastic x-ray scattering to observe a dispersive charge mode in hole-doped cuprates, revealing momentum-dependent charge excitations that vary with doping, consistent with theoretical models.

## Contribution

First experimental observation of a dispersive charge mode in hole-doped cuprates using RIXS at the oxygen K edge, supported by theoretical calculations.

## Key findings

- Dispersive charge mode shows positive energy dispersion with momentum.
- Spectral weight shifts to higher energy with increased hole doping.
- The mode is attributed to intraband charge excitations in the cuprates.

## Abstract

We investigate electronic excitations in La2-x(Br,Sr)xCuO4 using resonant inelastic x-ray scattering (RIXS) at the oxygen K edge. RIXS spectra of the hole-doped cuprates show clear momentum dependence below 1 eV. The spectral weight exhibits positive dispersion and shifts to higher energy with increasing hole concentration. Theoretical calculation of the dynamical charge structure factor on oxygen orbitals in a three-band Hubbard model is consistent with the experimental observation of the momentum and doping dependence, and therefore the dispersive mode is ascribed to intraband charge excitations which have been observed in electron-doped cuprates.