title: Room-temperature stabilization of nanoscale superionic Ag₂Se.
abstract: Superionic materials are multi-component solids in which one sub-lattice exhibits high ionic conductivity within a fixed crystalline structure. This is typically associated with a structural phase transition occurring significantly above room temperature. Here, through combined temperature-resolved x-ray diffraction and differential scanning calorimetry, we map out the nanoscale size-dependence of the Ag₂Se tetragonal to superionic phase transition temperature and determine the threshold size for room-temperature stabilization of superionic Ag2Se. For the first time, clear experimental evidence for such stabilization of the highly ionic conducting phase at room temperature is obtained in ∼2 nm diameter spheres, which corresponds to a >100 °C suppression of the bulk phase transition temperature. This may enable technological applications of Ag₂Se in devices where high ionic conductivity at room temperature is required.
authors.affiliation: Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA. Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA.
authors.forename: T
authors.initials: T
authors.lastname: Hu
authors.forename: J S
authors.initials: JS
authors.lastname: Wittenberg
authors.forename: A M
authors.initials: AM
authors.lastname: Lindenberg