The Allred group specializes in the discovery and characterization of new inorganic materials with functional properties. Solid state devices are ubiquitous in energy and information technologies, but we often lack the chemical tools to control and manipulate the underlying charge and/or spin dynamics. This requires a fundamental understanding of how these emergent properties can be tied back to the local bonding environment.
We emphasize using state-of–the-art x-ray and neutron diffraction techniques to investigate the atomic positions both on the long-range averaged limit and the microscopic local scale in bulk solid state compounds. We leverage what we learn to guide our synthesis efforts of future materials with desired properties. For example:
Magnetic Materials: The long-range ordering of magnetic moments depends on the combination of competing interactions. Many facets of how this works are still not understood. What is known is that this complex interplay gives rise to the many different types of ordering that span various regimes of bonding—from localized to delocalized, ionic to covalent. One way to improve our understanding of these interactions is to tune material properties in order to stabilize unusual ground states. For example, one strategy is to tune across the boundary between localized and delocalized electronic states.
Multiferroic Materials: Sometimes magnetism is only one part of a rich tapestry of interconnected properties. Multiferroics are materials that exhibit multiple primary types of ferroic ordering, such as ferromagnetism or ferroelectricity. In many cases the way these parameters are coupled is obscured by details of the electronic or nuclear structure. Emerging diffraction technologies provide new avenues for teasing out the important parameters. These materials can be used in the next generation of sensor technologies, which depend on a combination of multiple order parameters—e.g. orbitals, spins, charge—that couple in a controllable manner.