B.R. Gelchinski, А. А. Yuryev, E.M. Zhilina, K.V. Beltyukova.
ABSTRACT
Liquid Bi is a promising object for investigation due to the experimentally found features on the temperature dependence of properties, the nature of which is still debatable. Earlier, using the method of the first-principle Molecular Dynamics (FPMD) we calculated the temperature dependence of some properties of liquid Bi that demonstrated the nonmonotonic behavior. Atomic coordinates obtained by the FPMD method were used in this paper for further study of the structural features by the Voronoi Polyhedrons (VP) method. These polyhedrons, constructed in such a way that they fill the space within the disordered structure without gaps or overlaps, are fundamental geometric figures that allow the analysis of atomic structure in terms of precise topological and metric characteristics. The following characteristics are calculated: distribution by distances to the nearest neighbors, distribution by the number of VP faces, distribution by the number of pentagonal faces, etc.
The analysis of the obtained VP characteristics allowed us to trace the tendency of the Bi melt structure variation at temperatures above the melting point and to reveal deviations from monotonic behavior on temperature dependences. In particular, it is interesting to observe the nonmonotonic behavior for the number of polyhedra with pentagonal faces, which increases sharply when overheated by about 150 K above the melting point. In general, the results allow us to conclude that in liquid Bi with small overheats takes place a smooth rearrangement of the short-range order structure, which is reflected in the behavior of the temperature dependence of the properties
KEY WORDS:
disordered systems, metals and alloys, energy storage materials, atomic scale structure, computer simulations, molecular dynamics simulations
DOI: 10.31857/S023501062102002X