Simulating Diffusion at Low Temperatures in Binary Lennard-Jones Glasses: The Activation-Relaxation Technique

摘要

Understanding the nature of diffusion in compact systems such as alloyed metals remains a serious challenge. A direct experimental observation of the different processes leading to diffusion in the bulk is generally ruled out. Moreover, the study of these processes in computer simulations has been hampered by the long time scale typical for diffusion in these systems, a scale often beyond the reach of standard methods such as molecular dynamics. In this contribution, we present the activation relaxation technique (ART), a method specifically designed for the simulation of activation mechanisms. ART defines moves directly in the energy landscape and is therefore not sensitive to the real-space complexity of an activated jump, nor to the height of the energy barrier. Details of the algorithm and its implementation are discussed here, as well as recent results obtained with ART in the study of binary Lennard-Jones glasses.