Polarizabilities of Isolated Semiconductor Clusters

Abstract

The static polarizabilities ${\ensuremath{\alpha}}_{c}$ of the isolated semiconductor clusters ${\mathrm{Si}}_{N},{\mathrm{Ga}}_{N}{\mathrm{As}}_{M},$ and ${\mathrm{Ge}}_{N}{\mathrm{Te}}_{M}$ have been investigated in dependence of cluster size and temperature. The results for the ${\mathrm{Si}}_{N}$ clusters are discussed within a two-band semiconductor model that includes a widening of the band gap due to quantum size effects. Additionally, the importance of defectlike electronic states is discussed for ${\mathrm{Si}}_{N}$ and ${\mathrm{Ga}}_{N}{\mathrm{As}}_{M}$ clusters. The temperature dependence of the polarizability values for several ${\mathrm{Ga}}_{N}{\mathrm{As}}_{M}$ and ${\mathrm{Ge}}_{N}{\mathrm{Te}}_{M}$ species gives evidence for vibronic (ionic) contributions to ${\ensuremath{\alpha}}_{c}$.