Professor Kirill Kovnir, University of California, Davis

"Rational Approaches for Novel Thermoelectric and Strongly Correlated Magnetic Materials"

About the Seminar:

The phenomenon of thermoelectricity is attributed to the interconversion of thermal and electrical forms of energy. We developed a new class of bulk thermoelectric materials based on clathrates with a three dimensional framework comprised of oversized transition metal-phosphorus polyhedral cages that encapsulate guest cations. Transition metal-based clathrates have the following advantages over conventional Si-, Ge-, and Sn-based clathrates: i) a larger variety of framework topologies; ii) a higher tunability of the electronic properties via framework substitutions. The correlation between the crystal structure, distribution of the metal and phosphorus atoms over the clathrate framework and thermoelectric properties will be discussed.

Exploration of chemical factors that affect magnetic interactions in solids is one of the major steps in the development of novel magnetic materials. We have developed a synthetic approach that granted access to novel well-crystalline materials containing an infinite Fe-chalcogenide sublattice where correlated magnetic interactions are expected. On the example of the solution synthesis of the simplest superconductor, tetragonal iron(II) selenide (β-FeSe), we will consider main advantages and pitfalls of the solution synthesis of superconductors and highly correlated materials. Perspectives of this method for the design and synthesis of new materials will be discussed.

About the Speaker:

Kirill Kovnir is an Assistant Professor at University of California, Davis. He was born in Kirovograd, Ukraine. He studied chemistry and received Ph.D. at the Lomonosov Moscow State University with Prof. A. V. Shevelkov scrutinizing inverse clathrates. Afterwards he was tunneling between Max Planck Institute for Chemical Physics of Solids in Dresden and Fritz Haber Institute of the Max Planck Society in Berlin exploring potential of intermetallic compounds in heterogeneous catalysis supervised by Prof. Yu. Grin and Prof. R. Schlögl. In 2008 he moved to Florida State University where he acquired a comprehensive knowledge of magnetism of complex solids under guidance of Prof. M. Shatruk. Kirill’s research interests are in the broad field of solid state and materials chemistry. Research in his group is focused on synthesis of novel thermoelectric, superconducting, magnetic, and low-dimensional materials and exploring their crystal structure, chemical bonding, and physical properties. Understanding the structure-property relationship is a key to the rational design of such materials.