Impurity effects on the melting of Ni clusters

TL;DR

This study shows how adding a single carbon impurity significantly alters the thermodynamic and atomic mobility properties of Ni clusters, with implications for tuning material behavior and nanotube growth.

Contribution

It reveals the dependence of Ni cluster thermodynamics on impurity type and provides insights into impurity-driven control of cluster properties.

Findings

Carbon impurities change melting behavior of Ni clusters

Impurities affect atom mobility and diffusion in Ni clusters

Diffusion coefficients inform nanotube growth estimates

Abstract

We demonstrate that the addition of a single carbon impurity leads to significant changes in the thermodynamic properties of Ni clusters consisting of more than a hundred atoms. The magnitude of the change induced is dependent upon the parameters of the Ni-C interaction. Hence, thermodynamic properties of Ni clusters can be effectively tuned by the addition of an impurity of a particular type. We also show that the presence of a carbon impurity considerably changes the mobility and diffusion of atoms in the Ni cluster at temperatures close to its melting point. The calculated diffusion coefficients of the carbon impurity in the Ni cluster can be used for a reliable estimate of the growth rate of carbon nanotubes.