Structure and stability of cluster-assembled solid Al12C(Si): A first-principles study

We have proposed a possible crystal structure for the cluster-assembled solid Al12C(Si), and its electronic structures and stability have been studied in the framework of density functional theory and ab initio molecular dynamics. We find that Al12C(Si) clusters are condensed by van der Waals force, with a very small cohesive energy of similar to 1.1 eV. The combined steepest descent on ions shows that upon the formation of solid the relaxation of atomic distances in the Al12C(Si) cluster is very small. The stability of the Al12C solid is also confirmed by a dynamical simulation at low temperature.