title: Ultrafast charge recombination in a photoexcited Mott-Hubbard insulator.
abstract: 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 the picosecond range, can be explained even quantitatively with the multimagnon 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.
authors.affiliation: J. Stefan Institute, SI-1000 Ljubljana, Slovenia.
authors.forename: Zala
authors.initials: Z
authors.lastname: Lenarčič
authors.forename: Peter
authors.initials: P
authors.lastname: Prelovšek