Glass transition in disordered clusters

Using molecular dynamics simulations, the melting behavior of disordered aluminum clusters with 30 similar to 100 atoms has been systematically studied. We find that, all the disordered clusters undergo a glass transition before completely melting. We identify two characteristic temperatures, i.e. T-s and T-g (the glass transition temperature). When the temperature is higher than T-s, the cluster shape starts to change, accordingly the configurational entropy emerges. For temperatures between T-s and T-g, the disordered clusters show a remarkable cooperative diffusion, more importantly, the activation energy of cooperative diffusions below T-g is always lower than that of the liquid state. We have tried to understand such behavior from potential landscape and configurational entropies. (C) 2019 Elsevier B.V. All rights reserved.