Geometrical and electronic properties of GanN2(n=1–18)(n=1–18) clusters: A density-functional investigation

The geometrical and electronic properties of GanN2(n=1–18)(n=1–18) clusters have been investigated using the density functional theory within the generalized gradient approximation. The lowest-energy structures of these clusters have been obtained, and the trends in the geometries are discussed. The results show that the two N atoms prefer a peripheral position with a bulklike coordination as the cluster size increases. The two N atoms have the same coordination of Ga atoms in the most cases. It suggests that N atoms may distribute on the surface with similar bulklike coordination for large Ga-rich clusters with more N atoms. The GanN2 clusters at n=4,6,8,10n=4,6,8,10 and 16 are found to possess relatively higher stability. The size-dependence of cluster properties such as binding energy, HOMO–LUMO gap, ionization potential, electron affinity, Mulliken charge and GaN bond length has been computed and analyzed. The bonding characteristics of the GanN2 clusters are discussed.