Ab initio determination of ion traps and the dynamics of silver in silver-doped chalcogenide glass

We present a microscopic picture of silver dynamics in GeSe3:Ag glass obtained from the ab initio simulation. The dynamics of Ag is explored at two temperatures: 300 and 700 K. In the relaxed network, Ag occupies trapping centers that exist between suitably separated host sites. At 700 K, Ag motion proceeds via a trapping-release dynamics between “supertraps” or cages consisting of multiple trapping center sites in a small volume. Our work offers a first-principles identification of trapping centers invoked in current theories, with a description of their properties and associated Ag dynamics. We compute the charge state of the Ag in the network and show that it is neutral if weakly bonded and Ag+ if in a trapping center.