Structural and electronic properties of boron- and nitrogen-doped Si _nC_n (n = 7-15) clusters: A theoretical investigation

摘要

The structural and electronic properties of Si_nC_n (n = 7-15) cage-like clusters doped with boron and nitrogen atoms have been investigated using spin-polarized density functional calculations. We found that the B@Si_nC_n and N@Si_nC_n clusters energetically favour cage-like structures, and the B/N dopant prefers to be located at the interior/surface site of the Si frame. Theoretical results indicate that four clusters are highly stable, which are B@Si_8C _8, N@Si_(14)C_(14), N@Si_8C_8, and N@Si_(12)C_(12) clusters. On the basis of the lowest-energy structures obtained, the size dependence of electronic properties such as binding energy, gap between the highest occupied molecular orbital and the lowest unoccupied molecular orbital (HOMO-LUMO gap), vertical ionization potential, electron affinity, Mulliken charge, etc has been calculated and analysed.