We study the formation of Cooper pairs in high-Tc cuprate superconductors within a spin uctuation model for doped quantum Heisenberg antiferromagnets. The charge of the dopants (chargons) is associated to quantum skyrmion excitations of the Cu++ antiferromagnetic spin background. We then compute the quantum skyrmion e effective interaction potential as a function of doping and temperature in order to study charge pairing. It becomes clear that Cooper pair formation is determined by the competition between the spin uctuations of the Cu++ magnetic ions and the spins of the O-- doped holes (spinons). The superconducting transition occurs when the effective potential allows for skyrmion bound states. Our theoretical predictions for the superconducting phase diagram of La2-x Sr x CuO4 and YBa2 Cu3O6+x are in good agreement with experiment.
