Energy decomposition analysis of metal silicide nanowires from first principles

We investigate the structure, stability, and electronic properties of yttrium silicide nanowires with AlB2-type structure, using ab initio calculations. The results confirm experimental findings that yttrium silicide nanowires are robust and conductive. In particular, the dependencies on nanowire thickness are analyzed. Furthermore, calculations show that the vacancy formation in stoichiometric nanowires is energetically favorable. The total energy of the nanowires is decomposed into the bulk, surface, and edge contributions. An equation is proposed for the cohesive energy E-c(n,m) of an arbitrary wire as a function of its cross-section dimensions n and m, which can be further reduced to the nearly linear relationship between the cohesive energy and composition. A comparison with recent epitaxial growth experiments is given.