The effect of ammonia intercalation on the superconducting properties of the alkali-metal doped fulleride

A theoretical investigation of the electronic properties of the relatively high-Tc alkali-metal doped superconducting fullerides when they are further exposed to ammonia molecules as dopants is presented. Our numerical method relies on a group theoretical technique for the formation of molecular orbitals (MO's) for the solid C60 using 60 radial atomic orbitals (AO's) derived in a previous work. We also take into consideration the fact that the Fermi energies of the fullerides compare favourably with their phonon energies in the choice of a Tc formula. The effect of the ammonia molecules, as intercalants, on the density of states at the Fermi level (N(ef)) and consequently superconductivity are then discussed JONAMP Vol. 11 2007: pp. 455-460