Local icosahedral structures in binary-alloy clusters from molecular-dynamics simulation

We investigate the structure of 13-particle clusters in binary alloys for various size ratios and different concentrations via molecular-dynamics simulation. Our goal is to predict which systems are likely to form local icosahedral structures when rapidly supercooled from the melt. We calculate the energy spectrum of the minimal energy structures, and characterize all detected minima from both their relative probability and a structural point of view. We identify regions in our parameter space where the icosahedral structure is dominant (like in the corresponding monatomic case), regions where the icosahedral structure disappears, and others where icosahedral structures are present but not dominant. Finally, we compare our results with simulations reported in the literature and performed on extended binary systems with various size ratios and at different concentrations.