A density-functional theory for (BAs)n clusters (n=1-14): structures, stabilities and electronic properties

This paper investigates the lowest-energy structures, stabilities and electronic properties of (BAs)(n) clusters (n=1-14) by means of the density-functional theory. The results show that the lowest-energy structures undergo a structural change from two-dimensional to three-dimensional when n=4. With the increase of the cluster size (n >= 6), the (BAs)(n) clusters tend to adopt cage-like structures, which can be considered as being built from B2As2 and six-membered rings with B As bond alternative arrangement. The binding energy per atom, second-order energy differences, vertical electron affinity and vertical ionization potential are calculated and discussed. The caculated HOMO-LUMO gaps reveal that the clusters have typical semiconductor characteristics. The analysis of partial density of states suggests that there are strong covalence and molecular characteristics in the clusters.