  We treat proton-neutron pairing amplitudes, in addition to the nuclear
deformation, as generator coordinates in a calculation of the neutrinoless
double-beta decay of 76Ge. We work in two oscillator shells, with a Hamiltonian
that includes separable terms in the quadrupole, spin-isospin, and pairing
(isovector and isoscalar) channels. Our approach allows larger single-particle
spaces than the shell model and includes the important physics of the
proton-neutron quasiparticle random-phase approximation (QRPA) without
instabilities near phase transitions. After comparing the results of a
simplified calculation that neglects deformation with those of the QRPA, we
present a more realistic calculation with both deformation and proton-neutron
pairing amplitudes as generator coordinates. The future should see
proton-neutron coordinates used together with energy-density functionals.
