School of Chemistry Colloquium: Prof. Xiaojun Kuang (Guilin University of Technology) Multiscale solutions for structural disorder in solid ionics

Structural disorder is commonly observed in solids, which plays important roles on the physical properties, particularly the ionic transport. Structural disorder arises from different factors, including multiple-type ion occupation at the same crystallographic site, partial site occupation due to the single-type ion distribution across different crystallographic sites, vacancy/interstitial defects, or dynamically orientational distribution of polyhedral units. In most cases, it occurs from a combination of multiple factors. The traditional average structures describing the mixed occupation or partial occupation are not able to reflect the real interatomic distances, bond angles, polyhedral geometry and ion distribution for the structural disorder. This place great demand on the structural disorder solution to uncover the fine local structures for understanding the physical properties. Although the state-of-art numerical and experimental techniques can probe the structures with complementary advantages over different scales, to fully characterize the complex structural disorder associated with peculiar properties remains challenging. This talk demonstrates multiscale solutions for the structural disorders in stuffed cristobalite silicates and tetragonal tungsten bronze oxyfluoride, and uncovers local orders hidden in the structure disorders, which helps on understanding and improving ionic conduction or electrochemical properties of solids.

This talk is open to final year undergraduate students, MSc students, PhD students, PDRAs and academic staff.