Non-technical Abstract: Modern condensed matter physics research has produced novel materials with fundamental properties that underpin a remarkable number of cutting-edge technologies. It is now generally accepted that novel materials are necessary for critical advances in technologies and whoever discovers novel materials generally controls the science and technology of the future. Transition metal oxides have attracted enormous interest within both the basic and applied science communities. However, for many decades, the overwhelming balance of effort was focused on the 3d-elements (such as iron, copper, etc.) and their compounds; the heavier 4d- and 5d-elements (such as ruthenium, iridium, etc., which constitute two thirds of the d-elements listed in the Periodic Table) and their compounds have been largely ignored until recently. The principal investigator seeks to discover novel materials containing 4d- and/or 5d-elements and understand how they offer wide-ranging opportunities for the discovery of new physics and, ultimately, new device paradigms. This project also provides rigorous training to all students involved, focusing on synthesis and characterization techniques covering a broad spectrum of materials and experimental probes available in the principal investigator's laboratory.
Physics driven by spin-orbit interactions is among the most important topics in contemporary condensed matter physics. Since the spin-orbit interaction is comparable to the on-site Coulomb and other relevant interactions, it creates a unique balance between competing interactions that drive complex behaviors and exotic states not observed in other materials. The project encompasses a systematic effort to elucidate physics of novel phenomena in spin-orbit-coupled and correlated materials and a rigorous search for new materials having exotic ground states. This project focuses on the following areas: (1) Novel phenomena at high pressures and high magnetic fields, (2) Unusual correlations between the insulating gap and magnetic transition in iridates and ruthenates, (3) Exotic metallic and superconducting states in iridates, (4) Mott insulators with "intermediate-strength" spin-orbit interaction and other competing energies, and (5) Single-crystal synthesis and search for novel materials. The principal investigator is one of a few key pioneers who have initiated seminal studies on iridates and, before that, ruthenates, and has comprehensive facilities and proven expertise for single-crystal synthesis and wide-ranging studies of structural, transport, magnetic, thermal and dielectric properties as functions of temperature, magnetic field, pressure and doping.
