  A space-periodic ground state is shown to exist for lattices of point ions in
$\R^3$ coupled to the Schr\"odinger and scalar fields. The coupling requires
the renormalization of the selfaction because of the singularity of the Coulomb
potential. The ground state is constructed by minimization of the renormalized
energy per cell. This energy is bounded from below when the charge of each ion
is positive. The elementary cell is necessarily neutral.
