Hybridization between K and C-60 electronic states in superconducting K3Ba3C60

We have studied the electronic structure of the superconducting fulleride K 3Ba3C60 using the local density approximation in the density functional the ory. We have found the presence of the hybridization not only between Ba an d C-60 states but also between K and C-60 states. This novel hybridization should have an effect on the electronic properties, including superconducti vity. Also in Rb3Ba3C60. the hybridization between Rb and C-60 is found as well. In addition, the density of states at Fermi level of K3Ba3C60 is foun d to be slightly larger than that of Rb3Ba3C60, although the lattice consta nt of K3Ba3C60 is shorter than that of Rb3Ba3C60 These results are in sharp contrast to A(3)C(60) superconductors (A=alkali-metal atoms).