  We study the breakdown of a Mott insulator with the thermodynamic imbalance
induced by an applied bias voltage. By analyzing the instabilities of the
magnetic susceptibility, we describe a rich non-equilibrium phase diagram,
obtained for different applied voltages, that exhibits phases with a spatially
patterned charge gap. For a finite voltage, smaller than the value of the
equilibrium Mott gap, the formation of patterns coincides with the emergence of
mid-gap states contributing to a finite steady-state conductance. We discuss
the experimental implications of this new scenario of Mott breakdown.
