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arXiv · 1801.07053

Enhanced pairing susceptibility in a photo-doped two-orbital Hubbard model

Philipp Werner·Hugo Strand·Shintaro Hoshino·Yuta Murakami·Martin Eckstein
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Abstract

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.

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Philipp Werner, Hugo Strand, Shintaro Hoshino, Yuta Murakami, Martin Eckstein. 2018-01-22. Enhanced pairing susceptibility in a photo-doped two-orbital Hubbard model. https://doi.org/10.1103/physrevb.97.165119

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