Molecular dynamics simulation of diffusion in liquid gallium arsenide

Abstract

Diffusion of Ga and As ions in simulated liquid gallium arsenide, GaAs, have been studied in a model containing 3000 ions under periodic boundary conditions via molecular dynamics simulation (MD). Diffusion constant D in system has been calculated over temperatures ranged from 5000 K down to 1400 K. Calculations of liquid GaAs model with a real density at 5.3176 g cm-3 show that the temperature dependence of the diffusion constant D show an Arrhenius law at relatively low temperatures above the melting point and show a power law, D ∼ (T -Tc )γ, at higher temperatures. And upon cooling the system from relatively high temperatures to low temperatures, we found across over from non-Arrhenian to Arrhenian dynamics in the liquids, i.e. corresponding to a transition from fragile to strong liquid behaviours in the system. Furthermore, we also found the glass phase transition temperature Tg for the GaAs system is anywhere around 1050 K. © 2009 Elsevier B.V. All rights reserved.