Growth and Magic Behavior of Metal Encapsulated Silicon Clusters

Abstract

Metal encapsulated silicon clusters M@Si_n (M = Ti and Cr and n = 8−16) have been studied using ab-initio ultrasoft pseudopotential method. Several structures for each cluster have been optimized to obtain the lowest energy isomers. Our results show that cage structures begin to form at the size of n = 12 for Cr@Si_n and 13 for Ti@Si_n. For Ti@Si_n our results are in excellent agreement with the available experimental results. In smaller size, metal doped silicon clusters have basket structures to be of the lowest energy. The bonding nature in these clusters is discussed from the electronic charge distribution.