Local atomic structure evolution of liquid gadolinium and yttrium during solidification: An ab initio study

Abstract

Local atomic structure evolution of pure gadolinium (Gd) and yttrium (Y) during solidification was investigated by using ab initio molecular dynamics (AIMD) simulation. The calculated results indicate that the local short-range order (SRO) in liquid Gd and Y is similar to some transitional metals with an asymmetric shape of the second peak in static structure factors. Moreover, the formation of icosahedral local motifs as a function of temperature decreases the diffusivity, which explains the connection between structure evolution and dynamic properties. In examining the topological structures of both systems, we demonstrate that small atomic displacement leads to two different types of topological sixfold rings in liquid and solid states. All analyses yield a systematic study about rare earth metals Gd and Y at the atomic level.