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.
@article{arxiv.cond-mat/0307497,
title = {Resonant inelastic x-ray scattering study of holon-antiholon continuum in SrCuO2},
author = {Young-June Kim and J. P. Hill and H. Benthien and F. H. L. Essler and E. Jeckelmann and H. S. Choi and T. W. Noh and N. Motoyama and K. M. Kojima and S. Uchida and D. Casa and T. Gog},
journal= {arXiv preprint arXiv:cond-mat/0307497},
year = {2009}
}