Ion dynamics in CuI: Testing the bond fluctuation model by an ab-initio molecular dynamics

The bond fluctuation model of superionic conductors provides a framework to understand the characteristic features of superionic conducting materials. According to the model, le superionic behaviour is related to a change of bonding that occurs locally and fluctuates in time. In the present study, the presence of such processes is investigated by studying the time evolution of the electronic states around a mobile Cu ion in the superionic conductor CuI by the ab initio molecular dynamics simulation. It is shown that the results of ab initio simulations agree well with the prediction of the model.