title: Waxing and waning of dynamical heterogeneity in the superionic state.
abstract: Using molecular dynamics simulations of UO2-a type II superionic conductor-we identify a well-defined onset of dynamic disorder (Tα), which is remarkably correlated to a nontrivial advance of dynamical heterogeneity (DH). Quantified by the correlations in the dynamic propensity and van Hove self-correlation function, the DH is shown to grow with increasing temperature from Tα, peak at an intermediate temperature between Tα and Tλ-the superionic transition temperature-and then recede. Surprisingly, the DH attributes are not uniform across the temperatures-our investigation shows a low temperature (αT) stage DH, which is characterized by weak correlations and a plateaulike period in the correlations of the propensity, and a high temperature (λT) stage DH with strong correlations that are analogous to those in typical supercooled liquids. Our work, which has rigorously identified the onset of superionicity, gives a different direction for interpreting scattering experiments on the basis of statistical, correlated dynamics.
authors.affiliation: Department of Nuclear Engineering, North Carolina State University, Raleigh, North Carolina 27695, USA.
authors.forename: V Ajay
authors.initials: VA
authors.lastname: Annamareddy
authors.affiliation: Department of Nuclear Engineering, North Carolina State University, Raleigh, North Carolina 27695, USA.
authors.forename: Prithwish K
authors.initials: PK
authors.lastname: Nandi
authors.affiliation: Department of Nuclear Engineering, North Carolina State University, Raleigh, North Carolina 27695, USA.
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Mei
authors.affiliation: Department of Nuclear Engineering, North Carolina State University, Raleigh, North Carolina 27695, USA.
authors.forename: Jacob
authors.initials: J
authors.lastname: Eapen