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

TL;DR

This study uses ab initio simulations to analyze silver ion dynamics in GeSe3:Ag glass, revealing trapping mechanisms and charge states that influence ion mobility at different temperatures.

Contribution

First-principles identification of trapping centers and charge states of silver ions in chalcogenide glass, providing microscopic insight into ion dynamics.

Findings

Silver occupies bond centers in the relaxed network.

At 700K, silver exhibits trapping-release dynamics within cages.

Silver is neutral when weakly bonded and becomes Ag+ in traps.

Abstract

We present a microscopic picture of silver dynamics in GeSe$_{3}$:Ag glass obtained from {\it ab initio} simulation. The dynamics of Ag is explored at two temperatures, 300K and 700K. In the relaxed network, Ag occupies bond centers between suitably separated host sites. At 700K, Ag motion proceeds via a trapping-release dynamics, between "super traps" or cages consisting of multiple bond-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. 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.