  The correlation-driven transition from a paramagnetic metal to a paramagnetic
Mott-Hubbard insulator is studied within the half-filled Hubbard model for a
thin-film geometry. We consider simple-cubic films with different low-index
surfaces and film thickness d ranging from d=1 (two-dimensional) up to d=8.
Using the dynamical mean-field theory, the lattice (film) problem is
self-consistently mapped onto a set of d single-impurity Anderson models which
are indirectly coupled via the respective baths of conduction electrons. The
impurity models are solved at zero temperature using the exact-diagonalization
algorithm. We investigate the layer and thickness dependence of the electronic
structure in the low-energy regime. Effects due to the finite film thickness
are found to be the more pronounced the lower is the film-surface coordination
number. For the comparatively open sc(111) geometry we find a strong layer
dependence of the quasi-particle weight while it is much less pronounced for
the sc(110) and the sc(100) film geometries. For a given geometry and thickness
d there is a unique critical interaction strength Uc2(d) at which all effective
masses diverge and there is a unique strength Uc1(d) where the insulating
solution disappears. Uc2(d) and Uc1(d) gradually increase with increasing
thickness eventually approaching their bulk values. A simple analytical
argument explains the complete geometry and thickness dependence of Uc2. Uc1 is
found to scale linearly with Uc2.
