  We propose a scheme for the deterministic generation of steady-state
entanglement between the two nuclear spin ensembles in an electrically defined
double quantum dot. Due to quantum interference in the collective coupling to
the electronic degrees of freedom, the nuclear system is actively driven into a
two-mode squeezed-like target state. The entanglement build-up is accompanied
by a self-polarization of the nuclear spins towards large Overhauser field
gradients. Moreover, the feedback between the electronic and nuclear dynamics
leads to multi-stability and criticality in the steady-state solutions.
