19. We have studied the possibile effects of high electric fields on Tc by solving the (four) s-wave Eliashberg equations in the case of a finite, non-half-filled energy band. We have assume a Coulomb pseudopotential depending on the filling in a very simple and plausible way. Reasonable values of the physical parameters involved are obtained. The application of this model sets a theoretical limit to the linear increase of Tc at the increase of the lattice spacing.
G.A. Ummarino, R.S. Gonnelli, D. Daghero
"Eliashberg equations and the phenomenology of field-effect-doped C60", International Journal of Modern Physics B, 16, 1539-1546, (2002).
G.A. Ummarino, R.S. Gonnelli
"The possible explanation of electric-field-doped C60 phenomenology in the framework of Eliashberg theory", Physical Review B 66, 104514, (2002). 
