Growth Pattern of Truncated Octahedra in AlN (N ≤ 310) Clusters

Abstract

The growth sequence of aluminum clusters containing up to 310 atoms was studied. The interaction of aluminum atoms is modeled by the NP-B potential fitted by highly accurate electronic structure datum for aluminum clusters and nanoparticles. The putative global minimum structures of Al(2-310) clusters are obtained by dynamic lattice searching (DLS) and DLS with constructed cores (DLSc) method. Lower energy structures of Al(63) and Al(64) were found in comparison with the previously reported Al(2-65) clusters. In the optimized structures of Al(63-310), all clusters are identified as truncated octahedra (TO) except for five decahedral structures at Al(64), Al(72), Al(74), Al(76), and Al(101), four stacking fault face-centered cubic structures at Al(91), Al(99), Al(129), and Al(135), and one icosahedron at Al(147). Therefore, the structural transition from small clusters to bulk metal may occur around Al(65). At the same time, the results show that aluminum clusters adopt TO growth pattern, and the growth is found to be based on six complete TO at Al(38), Al(79), Al(116), Al(140), Al(201), and Al(260).