Concentration Dependence of the Dynamic Properties of Liquid TlxSe1-xBased on Ab initio Molecular-Dynamics Simulations

Abstract

The concentration dependence of the dynamic properties of liquid TlxSe1-x alloys is investigated by ab initio molecular-dynamics simulations. In the concentration range \(x=0.0\) to 0.67, the highest diffusivity occurs at approximately \(x=0.2\) with the existence of fairly long Se chains in the liquid. Upon the further addition of Tl atoms, the self-diffusion coefficients of both Se and Tl decrease despite the shortening of the Se chain length. This behavior is due to the suppression of self-diffusion by the increase in the strength of electrostatic interactions between Tl and Se atoms. The concentration dependence of the ionic conductivity is discussed on the basis of the fluctuation–dissipation theorem as well as the Nernst–Einstein relation.