First-principles investigation on the electronic structures of intercalated fullerenes M3N@C80 (M = Sc, Y, and lanthanides)

C80 cages with encapsulated group III and lanthanide nitrides are systematically studied through density functional calculation. Most intercalated fullerenes M3N@C80 exhibit similar spectroscopic features near Fermi level, in consistent with experimental results. We establish that the plane of Sc3N is perpendicular to the C5 axis, rather than the C3 axis as proposed before. The charge transfer from metal atoms toward N and C atoms is quantitatively analyzed. The role of 4f states treated as valence states is explored through LSDA + U calculation finally.