We present a calculation of the recombination rate of the excited holon-doublon pairs based on the two-dimensional model relevant for undoped cuprates which shows that fast processes, observed in pump-probe experiments on Mott-Hubbard insulators in picosecond range, can be explained even quantitatively with the multi-magnon emission. The precondition is the existence of the Mott-Hubbard bound exciton of the s-type. We find that its decay is exponentially dependent on the Mott-Hubbard gap and on the magnon energy, with a small prefactor which can be traced back to strong correlations and consequently large exciton-magnon coupling.
@article{arxiv.1211.3236,
title = {Ultrafast charge recombination in photoexcited Mott-Hubbard insulator},
author = {Zala Lenarčič and Peter Prelovšek},
journal= {arXiv preprint arXiv:1211.3236},
year = {2013}
}