  Strongly correlated systems of fermions have a number of exciting collective
properties. Among them, the creation of a lattice that is occupied by doublons,
i.e. two quantum particles with opposite spins, offers interesting electronic
properties. In the past a variety of methods have been proposed to control
doublon formation, both, spatially and temporally. Here, a novel mechanism is
proposed and verified by exact diagonalization and nonequilibrium Green
functions simulations---fermionic doublon creation by the impact of energetic
ions. We report the formation of a nonequilibrium steady state with homogeneous
doublon distribution. The effect should be observable in strongly correlated
solids in contact with a high-pressure plasma and in fermionic atoms in optical
lattices.
