Investigation of Metal and Non-Metal Doped Dimer and Trimer C-60 Fullerene Chains as Prospective Spin Cluster Qubits

We have calculated the optimized geometries, electronic structures and spin distributions of metal and non-metal elements Li, Na, N and P doped C-60 fullerene dimers and trimers with different spin multiplicities using hybrid density functional theory (DFT) at the B3LYP/6-31G level of theory. Natural population analysis and Mulliken population analysis show that non-metal elements (N, P) inside the C-60 fullerene dimers and trimers are well isolated and preserve their electronic structures while charge transfer processes occur between metal elements (Li, Na) and C-60 structures. Energy calculations showed that both doped and undoped linear C-60 structures are energetically lower than triangular C-60 structures. Calculated spin density distributions make non-metal doped C-60 structures advantageous over metal doped C-60 cases as spin cluster qubits.