Structure, melting, and thermal stability of 55 atom Ag-Au nanoalloys

Alloy nanoclusters ("nanoalloys") are of interest because of their novel properties compared to bulk alloys. In this paper, the thermal behavior, including melting, of 55 atom Ag - Au nanoalloys has been investigated by molecular dynamics simulations using the Gupta many-body potential. Single melting runs exhibit a sharp transition from the cluster ground structures to the melt, while averaged results indicate that melting occurs in a size - and composition-dependent temperature range. The transition point (melting point) decreases with increasing Au concentration. Gold-rich Aun-Ag 55-n nanoalloys with n= 30-55 exhibit a very smooth transition from the ground state to their undercooled melt. Their thermal stability is influenced by the glass transition behavior of the pure amorphous Aun cluster. © 2007 American Chemical Society.