Density functional study of structural and electronic properties of AlnAs (1 ≤ n ≤ 15) clusters

Abstract

Energetically low-lying equilibrium geometric structures of AlnAs (n=1–15) clusters obtained by an all-electron linear combination of atomic orbital approach, within spin-polarized density functional theory, are reported. The binding energy, dissociation energy, and stability of these clusters are studied with the three-parameter hybrid generalized gradient approximation (GGA) due to Becke–Lee–Yang–Parr (B3LYP). Ionization potentials, electron affinities, hardness, and static dipole polarizabilities are calculated for the ground-state structures within the same method. The growth pattern for AlnAs (n=1–15) clusters is As-substituted the surface atom of Aln+1 clusters and it keeps the similar frameworks of the most stable Aln+1 clusters except for AlnAs (n=7, 8, and 15) clusters. The odd–even oscillations in the dissociation energy, the second differences in energy, the HOMO–LUMO gaps, the electron affinity, and the hardness are more pronounced. The stability analysis based on the energies clearly shows the clusters with an even number of valence electrons are more stable than clusters with odd number of valence electrons.