Structural, electronic and magnetic properties of Fen@C60 and Fen@C80 (n=2-7) endohedral metallofullerene nano-cages: First principles study

We studied the structural, electronic and magnetic properties of small Fe_n clusters (n=2-7) endohedrally doped in icosahedral C₆₀ and C₈₀ fullerenes using first principles calculations based on the density functional theory. It is found that the encapsulated Fe_n clusters inside icosahedral C₈₀ are energetically favorable while Fe_n@C₆₀ metallofullerene nano-cages are not. The binding energies of the Fe_n encapsulated in C₆₀ are positive and increase with the number of iron atoms (n) while those of the Fe_n@C₈₀ are negative and their absolute values increase up to n=6. The encapsulation does not significantly change the enclosed cluster structure, but the total magnetic moment of the larger clusters reduces due to a stronger Fe-C hybridization.