Local spin fluctuations provide the glue for orbital-singlet spin-triplet pairing in the doped Mott insulating regime of multi-orbital Hubbard models. At large Hubbard repulsion U, the pairing susceptibility is nevertheless very low, because the pairing interaction cannot overcome the suppression of charge fluctuations. Using nonequilibrium dynamical mean field simulations of the two-orbital Hubbard model, we show that out of equilibrium the pairing susceptibility in this large-U regime can be strongly enhanced by creating a photo-induced population of the relevant charge states, and that this susceptibility correlates with the local spin susceptibility. Since a strong enhancement of the pairing requires a low kinetic energy of the charge carriers, the phenomenon is supported by the ultra-fast cooling of the photo-doped carriers through the creation of local spin excitations.
@article{arxiv.1801.07053,
title = {Enhanced pairing susceptibility in a photo-doped two-orbital Hubbard model},
author = {Philipp Werner and Hugo Strand and Shintaro Hoshino and Yuta Murakami and Martin Eckstein},
journal= {arXiv preprint arXiv:1801.07053},
year = {2018}
}