Ab initio modeling of metallic Pd80Si20 glass

A realistic amorphous Pd80Si20 model is generated by means of ab initio molecular dynamics simulations, and its local structure is analyzed using various techniques. The model successfully reproduces the experimental pair distribution function and has an average coordination number of 12.10. The mean coordination number of Pd and Si atoms are 12.95 and 8.70, respectively. Si-centered atoms form principally two types of polyhedras; the tri-capped trigonal prism, ∼63%, and the standard square dodecahedron, 25%, whereas Pd-centered atoms present more complex packing with a coordination number ranging from 11 to 15. Common neighbor analysis suggests that icosahedral-, hexagonal-, and fcc defect-like bonding environments are the leading building units in Pd80Si20.

► Atomic structure of amorphous Pd80Si20 is generated using an ab initio molecular dynamics simulations. ► The model successfully reproduces the experimental pair distribution function. ► Si-centered atoms form principally the tri-capped trigonal prism and the standard square dodecahedron. ► Pd-centered atoms are found to form complex packing with a coordination number ranging from 11 to 15. ► Icosahedral-, hexagonal-, and fcc defect-like bonding environments are the leading building units in amorphous Pd80Si20.