Local fivefold symmetry in liquid and undercooled Ni probed by x-ray absorption spectroscopy and computer simulations
A Di Cicco and F Iesari and S De Panfilis and M Celino and S Giusepponi and A Filipponi, PHYSICAL REVIEW B, 89, 060102 (2014).
Presence and significance of fivefold configurations in liquid metals are investigated by combining x-ray absorption spectroscopy and computer simulations (molecular dynamics and reverse Monte Carlo) in liquid and undercooled liquid nickel. We show that icosahedral short-range ordering (ISRO), probed by common-neighbor (CNA) and spherical invariant ((W) over cap (6)) analysis, involves a limited fraction (14-18% in undercooled nickel for different structural models) of local atomic configurations. The emerging picture for the liquid structure is that of a mixture of nearly icosahedral structures embedded in a disordered network mainly composed of fragments of highly distorted icosahedra (40-45% of the total), structures reminiscent of the crystalline phase, and other configurations.
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