  We use the form factors of the quantum transfer matrix in the
zero-temperature limit in order to study the two-point ground-state correlation
functions of the XXZ chain in the antiferromagnetic massive regime. We obtain
novel form factor series representations of the correlation functions which
differ from those derived either from the q-vertex-operator approach or from
the algebraic Bethe Ansatz approach to the usual transfer matrix. We advocate
that our novel representations are numerically more efficient and allow for a
straightforward calculation of the large-distance asymptotic behaviour of the
two-point functions. Keeping control over the temperature corrections to the
two-point functions we see that these are of order $T^\infty$ in the whole
antiferromagnetic massive regime. The isotropic limit of our result yields a
novel form factor series representation for the two-point correlation functions
of the XXX chain at zero magnetic field.
