High stability of the goldalloy fullerenes: A density functional theory investigation of M12@Au20 (M = Na, Al, Ag, Sc, Y, La, Lu, and Au) clusters

Discovering highly stable metal fullerenes such as the celebrated C-60 is interesting in cluster science as they have potential applications as building blocks in new nanostructures. We here investigated the structural and electronic properties of the fullerenes M-12@Au-20 (M = Na, Al, Ag, Sc, Y, La, Lu, and Au), using a first-principles investigation with the density functional theory. It is found that these compound clusters possess a similar cage structure to the icosahedral Au-32 fullerene. La-12@Au-20 is found to be particularly stable among these clusters. The binding energy of La-12@Au-20 is 3.43 eV per atom, 1.05 eV larger than that in Au-32. The highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) gap of La-12@Au-20 is only 0.31 eV, suggesting that it should be relatively chemically reactive.