Ab initiosimulation of solid electrolyte materials in liquid and glassy phases

Abstract

We use plane-wave density functional methods to model Ge-Se-Ag-Cu liquids and glasses. The models are analyzed for structural and electronic properties and transition metal ion dynamics. Electronic properties are analyzed with the electronic density of states and projected density of states. The optical gap increases with increasing Ag content and decreases with increasing Cu content. We carry out thermal simulation at 300, 700, and 1000 K on these Ge-Se glasses doped with various concentrations of copper and silver. Our study shows that the most diffusive ions sample the widest variation in local density. The study of trap centers for Ag-rich and Cu-rich glasses shows that because of the higher coordination number of Cu, it is more rigidly trapped compared to Ag, with its lower coordination number.