Abstract: We performed systematically spin-polarized density functional calculations to study the structural configurations，electronic and magnetic properties of the single Ni doped endohedral Ni@B₄₀ and exohedral Ni‒B₄₀ metallofullerene complexes. The results revealed different stable configurations of the Ni‒doped metallofullerenes depending on the positions of the doped Ni atoms. The calculated binding energies of all the considered Ni‒doped metallofullerenes are ranged from 5. 18 to 7. 12 eV/atom，which indicates the chemical interactions between the doped‒Ni atom and the B atom of B₄₀. Thus we conclude that a single Ni atom can be chemically adsorbed on the surface or encapsulated in the hollow cage of B₄₀ to form stable Ni‒doped metallofullerenes. By introducing dopant states，the energy gap of the Ni‒doped metallofullerenes has been partly reduced，due to the local distortions and charge transfer. As a consequence of the high hybridization and confinement effect，the hybrid Ni‒doped metallofullerene complexes have an attractive characteristic of the magnetic properties：nonmagnetic complexes systems with the inherent magnetic moments of the Ni atom completely disappeared，whether the Ni adsorbed on the surface of B₄₀ or encapsulated in the cage. These fascinating findings of the tunable electronic and magnetic properties of the Ni‒doped B₄₀ metallofullerenes imply that this type of metallofullerenes may be a promising candidate for electronic devices，especially expected to be applicable as a single molecular device.

Key words: all-boron fullerene B₄₀, metallofullerene, single molecular device, ab initio calculation