Insights into the structural, electronic and magnetic properties of Ni-doped gold clusters: Comparison with pure gold clusters

The structural, electronic and magnetic properties of Aun+1 and AunNi (n = 1-9) clusters have been investigated using an unbiased CALYPSO structure searching method in conjunction with density functional theory. The structural searches show that Ni atom in the lowest energy AunNi cluster favors the most highly coordinated position. The ground state Aun+1 and AunNi clusters possess a planar structure, except for Au6Ni and Au8Ni. Vibrational spectra and photoelectron spectra are predicted to identify their structures in the future. The relative stability and chemical activity are analyzed based on the averaged binding energy, dissociation energy and energy gap for the most stable clusters. It is found that the dopant atom can enhance the thermal stability of the gold clusters. The magic number of stability is 5 for both Aun+1 and AunNi clusters. The substitution of a Ni atom for an Au atom significantly decreases energy gap of Aun clusters with even n. The magnetism calculations show that the magnetic moments of Ni atom in AunNi clusters are reduced by 0.56-2 μB. This reduction may be attributed to the internal charge transfer from 4s to 3d orbital.