We show that a metastable η--pairing superconducting phase can be induced by photodoping doublons and holes into a strongly repulsive fermionic Hubbard model. The doublon-hole condensate originates from an intrinsic doublon-hole exchange interaction and does not rely on the symmetry of the half-filled Hubbard model. It extends over a wide range of doublon densities and effective temperatures. Different non-equilibrium protocols to realize this state are proposed and numerically tested. We also study the optical conductivity in the superconducting phase, which exhibits ideal metallic behavior, i.e., a delta function at zero-frequency in the conductivity, in conjunction with a negative conductivity at large frequencies. These characteristic optical properties can provide a fingerprint of the η-pairing phase in pump-probe experiments.
@article{arxiv.1908.08693,
title = {$\eta$--paired superconducting hidden phase in photodoped Mott insulators},
author = {Jiajun Li and Denis Golez and Philipp Werner and Martin Eckstein},
journal= {arXiv preprint arXiv:1908.08693},
year = {2020}
}