Resonant inelastic x-ray scattering study of holon-antiholon continuum in SrCuO2

TL;DR

This study uses resonant inelastic x-ray scattering and theoretical modeling to investigate charge excitations in SrCuO2, revealing a holon-antiholon continuum rather than a long-lived exciton, advancing understanding of one-dimensional Mott insulators.

Contribution

It provides new experimental and theoretical insights into the charge excitation spectrum of SrCuO2, highlighting the holon-antiholon continuum over excitonic states.

Findings

Observation of a dispersive charge excitation continuum

Absence of a long-lived exciton in SrCuO2

Identification of a broad resonance associated with holon-antiholon pairs

Abstract

We report a resonant inelastic x-ray scattering study of charge excitations in the quasi-one-dimensional Mott insulator SrCuO2. We observe a continuum of low-energy excitations, in which a highly dispersive feature with a large sinusoidal dispersion (~1.1 eV) resides. We have also measured the optical conductivity, and studied the dynamic response of the extended Hubbard model with realistic parameters, using a dynamical density-matrix renormalization group method. In contrast to earlier work, we do not find a long-lived exciton, but rather these results suggest that the excitation spectrum comprises a holon-antiholon continuum together with a broad resonance.