  We have studied the enhancement of the superconducting transition
temperature, Tc, in a t-J-U model of electrons moving on a square lattice in
which anisotropic electronic hopping is introduced. The inclusion of such
hopping mimics, in a approximate fashion, a potentially important
characteristic of materials possessing stripelike charge and spin correlations.
For this model we have calculated Tc for singlet pairing using the non
self-consistent Thouless criterion, and find a dramatic enhancement of Tc
induced by hopping anisotropies. Further, the maximum increase in Tc is
obtained when the system is pushed towards the extreme anisotropy limit, that
is, when the hopping of electrons is confined to occur in 1+0^+ dimensions. We
demonstrate that in this limit the increase in Tc, with respect to the
isotropic system, can be of the order of 1000. We have also determined that in
the extreme anisotropy limit the superconducting gap is an equal mixture of s
and d pairing symmetries (two choices of such a combination being s + d and s +
id) owing to the reduced (square to rectangular) symmetry of the system in the
presence of hopping anisotropies. Thus, the presence of d-wave superconducting
features in materials whose symmetry is very different from that of a
two-dimensional square lattice, with the anisotropy produced by the appearance
of stripes, is not unexpected.
