Structural growth pattern of neutral and negatively charged yttrium-doped silicon clusters YSi (=6-20): from linked to encapsulated structures.

A global search for the low energy of neutral and anionic doped Si clusters YSi ( = 6-20) was performed using the ABCluster global search technique coupled with a hybrid density functional method (mPW2PLYP). In light of the calculated energies and the measured photoelectron spectroscopy values, the true minima of the most stable structures were confirmed. It is shown that the structural growth pattern of YSi ( = 6-20) is from Y-linked two subcluster structure to a Y-encapsulated structure in Si cages, while that of YSi ( = 6-20) is from substitutional to linked structures, and as the number of Si atoms increases, it evolves toward the encapsulated structure. Superatom YSi with a high-symmetry endohedral structure has an ideal thermodynamic stability and chemical reactivity, making it the most suitable building block for novel optical, optoelectronic photosensitive or catalytic nanomaterials.