Design of Three-shell Icosahedral Matryoshka Clusters A@B₁₂@A₂₀ (A = Sn, Pb; B = Mg, Zn, Cd, Mn)

摘要

We propose a series of icosahedral matryoshka clusters of A@B₁₂@A₂₀ (A = Sn, Pb; B = Mg, Zn, Cd), which possess large HOMO-LUMO gaps (1.29 to 1.54?eV) and low formation energies (0.06 to 0.21?eV/atom). A global minimum search using a genetic algorithm and density functional theory calculations confirms that such onion-like three-shell structures are the ground states for these A₂₁B₁₂ binary clusters. All of these icosahedral matryoshka clusters, including two previously found ones, i.e., [As@Ni₁₂@As₂₀]3? and [Sn@Cu₁₂@Sn₂₀]12?, follow the 108-electron rule, which originates from the high I_h symmetry and consequently the splitting of superatom orbitals of high angular momentum. More interestingly, two magnetic matryoshka clusters, i.e., Sn@Mn₁₂@Sn₂₀ and Pb@Mn₁₂@Pb₂₀, are designed, which combine a large magnetic moment of 28 μ_B, a moderate HOMO-LUMO gap, and weak inter-cluster interaction energy, making them ideal building blocks in novel magnetic materials and devices.