Magnetic properties of Co-Si alloy clusters

We have investigated the electronic structure and the magnetic properties of Co-Si alloy clusters using ab initio spin-polarized density functional calculations. The possible CoSi2, CoSi, and Co2Si phase clusters with oblique hexagon prism, icosahedron, and cuboctahedron structures are introduced. The CoSi phase cluster with icosahedron structure has the largest binding energy and amount of charge transfer. We found that HOMO-LUMO gap, magnetic moment, and spin polarization for the Co-Si alloy clusters with icosahedron structure increase with Co concentration. The Si atoms in the CoSi phase with icosahedron structure have negative magnetic moment.