  The phenomenology of overdoped high Tc superconductors can be described by a
one band d wave Eliashberg theory where the mechanism of superconducting
coupling is mediated by antiferromagnetic spin fluctuations and whose
characteristic energy Omega0 scales with Tc according to the empirical law
Omega0 = 5.8 kBTc. This model presents universal characteristics that are
independent of the critical temperature such as the link between the s and d
components of electron boson coupling constants and the invariance of the ratio
2Delta/kBTc.
