Probing the structural and electronic properties of anionic europium-doped silicon clusters by density functional theory and comparison of experimental photoelectron spectroscopy

Density functional theory (DFT) calculations combined with stochastic kicking (SK) global search technique were performed to investigate the structural properties of EuSin- (1 <= n <= 13). It was found that the Eu atom in EuSi, , preferred to occupy the surface position up to a size of 11Si atoms. However, starting fromn = 12, the endohedral structures were found, as depicted by the Eu atom inserting into the center of Si frame. The global minimum structures for each size was determined by comparing with the experimental photoelectron spectroscopy (PES). Natural population analysis (NPA) coupled with spin density isosurfaces were utilized to further investigate the electronic and magnetic properties of EuSin-. The observed magnetic moments significantly concentrates among the Eu atom, ascribed to the Eu 4f-electrons remaining largely as before encapsulating the Si-n clusters. Meanwhile, the representative caged cluster EuSi12- was subjected to density of states (DOS) and HOMO-LUMO analysis, and the results showed a significant spin polarization.