Impurity effect on the melting of nickel clusters as seen via molecular dynamics simulations

摘要

We demonstrate that the addition of a carbon impurity leads to significant changes in the thermodynamic properties of a Ni_(147) cluster. The magnitude of the change induced is dependent on the parameters of the Ni-C interaction. Hence, thermodynamic properties of Ni clusters can be effectively tuned by the addition of a particular type of impurity. 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 as a reliable estimate of the growth rate of carbon nanotubes.