Diffusion mechanism of ag ions in superionic conductor Ag2Se from ab initio molecular-dynamics simulations

The dynamic properties of mobile Ag ions in the superionic conductor Ag2Se are studied by ab initio molecular-dynamics simulations. The population analysis including the gross charge and the overlap population shows that the bonding properties of Ag ions change accompanied with the diffusive motion. By investigating the displacement-correlation functions between Ag ions, it is clarified that Ag ions exhibit a collective motion with their neighbor Ag ions when they migrate between neighboring tetrahedral sites.