Si-centered capped trigonal prism ordering in liquid Pd82Si18 alloy study by first-principles calculations

First-principles molecular dynamic (MD) simulation and X-ray diffraction were employed to study the local structures of Pd-Si liquid at the eutectic composition (Pd82Si18). A strong repulsion is found between Si atoms, and Si atoms prefer to be evenly distributed in the liquid. The dominate local structures around Si atoms are found to be with of a trigonal prism capped by three half-octahedra and an archimedean antiprism. The populations of these clusters increase significantly upon cooling, and may play an important role in the formation of Pd82Si18 alloy glass.